The Complete Guide to Dermal Filler Safety, Vascular Occlusion & Ultrasound Guided Filler Dissolving
Everything you need to know about filler emergencies, warning signs, and the gold standard in safe filler removal — by Dr Karwal
Dermal filler is one of the most popular non-surgical aesthetic treatments in the UK. When administered by a medically qualified and highly skilled practitioner, it is safe, effective, and transformative. But like any injectable treatment, it carries a small risk of complications — and understanding those risks is essential for any patient.
At Karwal Aesthetics, patient safety is not just a priority — it is the foundation of everything Dr Karwal does. This comprehensive guide covers everything you need to know about filler complications, filler emergencies, vascular occlusion, and the most advanced method of filler dissolving available today: ultrasound guided hyaluronidase treatment.
Whether you are considering your first filler treatment, have concerns about existing filler, or are experiencing symptoms that worry you, this guide is for you.
Part 1: Understanding Dermal Filler Complications
The Full Spectrum of Filler Complications
Filler complications range from very mild and temporary to rare and serious. Understanding the full range helps you know what is normal after treatment, what needs monitoring, and what requires immediate medical attention.
Mild and Common Reactions
The most common side effects after dermal filler are mild bruising, swelling, redness, and tenderness at the injection site. These are a normal response to the injections and typically resolve within a few days. Cold compresses, arnica gel, and avoiding alcohol and strenuous exercise can all help reduce these effects.
Asymmetry and Over-correction
In some cases, filler may not settle evenly, leading to visible asymmetry or an overfilled appearance. This is more likely when treatment is performed by an inexperienced practitioner or when too much product is used. Hyaluronic acid filler can be dissolved and corrected — Dr Karwal offers filler dissolving consultations specifically for this purpose.
Nodules and Granulomas
Small lumps or nodules can occasionally form at injection sites, sometimes caused by filler placed too superficially or by a localised reaction to the product. Some nodules resolve on their own; others may require hyaluronidase treatment to dissolve them. Granulomas are a rarer immune response to filler and may require specialist management.
The Tyndall Effect
The Tyndall effect is a well-recognised optical complication that can occur when hyaluronic acid filler is injected too superficially — particularly in areas of thin skin such as the tear troughs, under-eye area, or lips. Rather than appearing natural and invisible beneath the surface, the filler scatters light and creates a bluish or greyish discolouration visible through the skin. The effect is named after the physicist John Tyndall, who first described the phenomenon of light scattering through particles in suspension.
This complication does not carry the same urgency as a vascular occlusion, but it can be a significant cosmetic concern and is unlikely to resolve on its own. The good news is that the Tyndall effect is entirely treatable with hyaluronidase. At Karwal Aesthetics, Dr Karwal uses ultrasound guidance to confirm the depth and location of the superficially placed filler before dissolving it with precision, ensuring the enzyme is delivered exactly where it is needed and avoiding disruption to any surrounding tissue.
Infection
While rare, infection can occur following any injectable treatment. Signs include increasing redness, warmth, swelling, and pain that worsens rather than improves in the days after treatment. If you suspect an infection, seek medical advice quickly — early antibiotic treatment is usually very effective.
Part 2: Vascular Occlusion — The Most Serious Filler Complication
What Is a Vascular Occlusion?
A vascular occlusion is the most serious complication associated with dermal filler treatment. It occurs when filler accidentally enters or compresses a blood vessel, blocking the flow of blood to the surrounding tissue. Without blood supply, the affected area is deprived of oxygen and nutrients, which can cause the tissue to become damaged or — in severe cases — to die. This is classified as a medical emergency that requires immediate treatment.
How Does Filler Enter a Blood Vessel?
The face is richly supplied with blood vessels. When injecting filler, there is always a small risk of the needle or cannula inadvertently entering one of these vessels. In some cases, filler may also compress a vessel from outside without entering it directly. Both scenarios can restrict or block blood flow to the surrounding tissue.
The risk is highest in areas where blood supply is most limited, such as the tip of the nose, the nasal bridge, and the area around the eyes and lips. This is why choosing an experienced, medically qualified practitioner with a thorough understanding of facial anatomy is so important.
The Warning Signs of a Vascular Occlusion
Knowing the warning signs of a vascular occlusion could make all the difference. Symptoms can appear during or shortly after a filler treatment. If you notice any of the following, contact a medical professional immediately:
Warning Sign 1: Unusual or Intense Pain
Some discomfort during filler injections is completely normal. However, severe, disproportionate pain that does not ease after the injection is a red flag. If the pain feels out of proportion to what you would expect, or if it radiates beyond the treatment area, speak to your practitioner immediately.
Warning Sign 2: Skin Blanching
A sudden white or pale patch of skin near or around the injection site is one of the most recognisable early signs of a vascular occlusion. This blanching indicates that blood flow has been interrupted. If you or your practitioner notices this during or after treatment, it requires urgent attention.
Warning Sign 3: Dusky, Blue or Mottled Skin
As oxygen deprivation continues, the skin may change colour — moving from white to a grey, blue, or mottled purple tone. This is a sign that tissue damage may be occurring. The appearance is often described as looking like a bruise or a map-like pattern on the skin. This should be treated as an emergency.
Warning Sign 4: Impaired Capillary Refill Time
Capillary refill time (CRT) is a simple but important clinical assessment used to evaluate blood flow to the skin. A trained practitioner presses briefly on the skin or the area near a fingernail and releases — in healthy tissue, colour returns within two seconds as blood refills the capillaries. When a vascular occlusion has occurred, this refill is slowed or absent in the affected area, confirming that blood supply has been compromised.
Assessing capillary refill time is a key part of Dr Karwal's clinical assessment during and after filler treatment. An impaired CRT in the treatment area — even in the absence of obvious colour change — can be an early and critical indicator of a vascular occlusion. This is why having an experienced, medically trained practitioner matters: these subtler clinical signs may not be recognised by a less qualified injector, and missing them can mean precious time is lost.
Warning Sign 5: Vision Changes
In rare but extremely serious cases, filler can travel to the blood vessels that supply the eyes, causing sudden vision changes or even blindness. If you experience any change in vision following a filler treatment, seek emergency medical care immediately and inform the medical team that you have had recent filler injections.
Why Speed of Treatment Is Everything
When blood flow is cut off to an area of tissue, a process of progressive damage begins almost immediately. The tissue becomes starved of oxygen, and if blood flow is not restored quickly, cells begin to die. The widely accepted clinical guidance is that hyaluronidase should be administered as quickly as possible — ideally within the first hour of symptoms appearing.
Tissue damage that begins as a temporary colour change can progress to blistering, then to tissue death and scarring if the occlusion is not treated promptly. This is why at Karwal Aesthetics, every suspected vascular occlusion is treated as a genuine emergency — immediately, without hesitation.
"If you experience severe pain, skin blanching, or unusual discolouration after a filler treatment — whether carried out at our clinic or elsewhere — please contact us immediately. Do not wait to see if symptoms improve."
What Happens If the Occlusion Is Not Treated Promptly?
Patients sometimes wait to see if symptoms will improve on their own, or they are reluctant to raise the alarm. This delay can have serious consequences. Without prompt treatment, what begins as tissue discolouration can progress to blistering, ulceration, and ultimately tissue necrosis — the irreversible death of skin and underlying tissue, which can leave permanent scarring.
This is why it is critical to act immediately upon noticing any of the warning signs described above. If you are not able to reach your practitioner, go to your nearest emergency department and inform them that you have had dermal filler treatment.
What to Do in a Filler Emergency
If you or someone you know is experiencing signs of a vascular occlusion, take the following steps immediately:
Contact a medically qualified aesthetics practitioner without delay. At Karwal Aesthetics, Dr Karwal is trained to manage filler emergencies and has access to hyaluronidase and ultrasound guidance for rapid, precise treatment. If you are not able to reach your practitioner, go to your nearest emergency department.
It does not matter whether your original treatment was carried out at Karwal Aesthetics or at another clinic. If you are experiencing signs of a vascular occlusion and cannot reach your original practitioner, Dr Karwal will not turn away a patient in an emergency. Patient safety always comes first.
Part 3: Treating Vascular Occlusion — Hyaluronidase and the Role of Ultrasound
What Is Hyaluronidase?
Hyaluronidase is an enzyme that breaks down hyaluronic acid — the material most dermal fillers are made from. When injected near or into a vascular occlusion, it dissolves the filler and relieves the blockage, allowing blood to flow freely again. It is the primary emergency treatment for this type of complication and must be available at any clinic offering dermal filler treatments.
Dr Karwal carries hyaluronidase at all times during treatments and follows the latest evidence-based protocols for vascular occlusion management. This includes immediate assessment, administration of hyaluronidase, warm compresses, and close monitoring of the affected area.
Allergy Testing Before Hyaluronidase: Intradermal Testing
Before hyaluronidase is administered — whether in an emergency or as part of a planned dissolving treatment — it is important to consider the small but real risk of an allergic reaction to the enzyme. Hyaluronidase is derived from animal sources (typically bovine or ovine), and as with any biological substance, some patients may have a pre-existing sensitivity or develop one.
At Karwal Aesthetics, Dr Karwal takes allergy risk seriously and will discuss your allergy history as part of every consultation. Where time permits — for example in planned, elective filler dissolving — allergy testing can be carried out prior to treatment.
Intradermal Testing
Intradermal testing is a more sensitive method of allergy assessment. A tiny amount of diluted hyaluronidase is injected just beneath the surface of the skin, and the site is observed for a reaction over a set period. A raised, red wheal at the test site indicates a positive reaction, suggesting that the patient may be at higher risk of an allergic response to a full dose. Intradermal testing is generally considered more reliable than surface patch testing for predicting immediate hypersensitivity reactions.
Allergy Testing in Emergency Situations
It is important to note that in a genuine filler emergency — where a vascular occlusion is suspected and every minute counts — there is no time to wait for allergy testing. In these circumstances, the risk of not treating the occlusion immediately far outweighs the risk of a potential allergic reaction to hyaluronidase. Dr Karwal is fully equipped to manage allergic reactions should they occur, including having appropriate emergency medication readily available. After emergency treatment, allergy history is reviewed and documented as part of the follow-up care.
The Limitations of Treating Without Ultrasound
Historically, vascular occlusions were treated by injecting hyaluronidase in and around the affected area, relying on the practitioner's clinical judgement and anatomical knowledge to estimate where the blockage was. While this approach can work, it is imprecise. Large amounts of hyaluronidase may be needed, there is no guarantee the product reaches the exact point of occlusion, and it can inadvertently dissolve filler in areas that are not causing a problem.
The face contains a complex network of blood vessels, nerves, and anatomical structures that lie beneath the surface. When filler causes a complication, the problem is invisible to the naked eye. Injecting hyaluronidase without imaging is like trying to fix a blocked pipe without being able to see the pipe — you may get lucky, but you may also miss the problem entirely or cause unnecessary disruption elsewhere.
How Ultrasound Transforms Emergency Treatment
High-frequency ultrasound imaging allows Dr Karwal to see beneath the skin in real time, creating a live image of the underlying tissue. Filler appears as a distinct, easily identifiable structure on the ultrasound image, meaning its location can be established quickly and accurately. When a vascular occlusion is suspected, this technology allows Dr Karwal to locate the exact site of the blockage before delivering hyaluronidase — guiding the injection directly to the problem area with pinpoint precision.
By delivering hyaluronidase directly to the site of the problem, treatment is faster and more effective. The correct amount of enzyme reaches exactly the right location, meaning blood flow can potentially be restored more quickly. This precision also reduces the risk of inadvertently dissolving filler in other areas of the face that are not causing any issues.
Aftercare Following Emergency Hyaluronidase Treatment
Following emergency treatment, Dr Karwal will monitor the affected area closely. Patients may be asked to attend follow-up appointments to assess how the tissue is healing and to evaluate whether further hyaluronidase is needed. Most patients recover well when treatment is given promptly, but ongoing monitoring is an important part of the process.
Part 4: Ultrasound Guided Filler Dissolving — The Gold Standard
What Is Ultrasound Guided Filler Dissolving?
Filler dissolving has become an increasingly sought-after treatment as more people look to reverse, correct, or refresh previous filler treatments. But not all filler dissolving is the same. Ultrasound guided filler dissolving uses real-time imaging technology to ensure hyaluronidase is delivered with maximum precision — dissolving only what needs to be dissolved, and preserving everything else.
Traditional filler dissolving involves injecting hyaluronidase based on clinical judgement alone — using touch, observation, and anatomical knowledge to estimate where the filler is. Ultrasound guided dissolving adds a vital extra layer: before and during treatment, Dr Karwal uses ultrasound to actually see where the filler is sitting, allowing for precise, targeted delivery of the dissolving agent.
Standard vs Ultrasound Guided Filler Dissolving: A Clear Comparison
Standard Filler Dissolving
In standard filler dissolving, hyaluronidase is injected into and around the area where filler is believed to be located. The placement is guided by the practitioner's clinical assessment — touch, visual inspection, and knowledge of typical filler injection sites. In experienced hands, this can be effective for straightforward cases of lip or cheek filler dissolving.
However, the main limitation is that it relies on assumptions about where the filler is. Filler can migrate over time, or it may have been placed at an unusual depth or location by the original practitioner. In these cases, a practitioner working without imaging may miss the target entirely, or may inadvertently dissolve filler that was not causing any problem.
Ultrasound Guided Filler Dissolving
Ultrasound guided dissolving adds a real-time imaging layer to the entire process. Before treatment begins, Dr Karwal uses an ultrasound probe to map the filler deposits within the tissue — establishing exactly where they are, how much is present, and at what depth. The hyaluronidase is then injected under ultrasound guidance, meaning Dr Karwal can watch the needle in real time and confirm the enzyme is being placed exactly where it needs to be.
The Science Behind Ultrasound Guided Filler Dissolving
What Is Hyaluronic Acid Filler?
Most dermal fillers used today are based on hyaluronic acid — a naturally occurring substance found in the skin, joints, and connective tissue. In aesthetic medicine, hyaluronic acid is formulated into a gel of varying consistencies and cross-linked to increase its longevity in the tissue. It is safe, biocompatible, and — crucially — reversible.
How Hyaluronidase Works
Hyaluronidase is an enzyme that catalyses the breakdown of hyaluronic acid. When injected near a deposit of hyaluronic acid filler, it disrupts the chemical bonds that hold the filler gel together, causing it to break down into its constituent components. These are then absorbed naturally by the body. The process begins within minutes of injection and continues over the following hours and days.
Why Filler Is Visible on Ultrasound
Diagnostic ultrasound works by emitting high-frequency sound waves from a handheld probe. These waves travel through tissue and are reflected back at different rates depending on the density and composition of the structures they encounter. Hyaluronic acid filler has a characteristic appearance on ultrasound — it typically appears as a hyperechoic (bright) or well-defined structure within the soft tissue, making it distinctly identifiable from the surrounding natural anatomy.
When ultrasound imaging is combined with hyaluronidase injection, the result is a treatment that is both scientifically precise and clinically superior. Dr Karwal can watch the needle approach the filler deposit on the ultrasound screen, deliver the enzyme directly into or immediately adjacent to the filler, and confirm that the dissolving process is initiated — representing the highest achievable standard of accuracy in filler removal.
Dissolving Filler Before Surgery: What You Need to Know
One of the most important — and often overlooked — indications for planned filler dissolving is preparation for surgical procedures. Patients who have dermal filler in place and are planning facial surgery such as a facelift (rhytidectomy), surgical rhinoplasty (nose job), blepharoplasty (eyelid surgery), or fat transfer procedures are frequently advised to have their filler dissolved beforehand. At Karwal Aesthetics, Dr Karwal works with patients at this stage of their journey, providing precise, ultrasound guided dissolving to prepare them safely for surgery.
Why Surgeons Ask for Filler to Be Dissolved
There are several important clinical reasons why a facial surgeon may request that all dermal filler is removed before operating. Filler alters the soft tissue landscape of the face, potentially making it harder for the surgeon to accurately assess facial anatomy, plan their incisions, and predict how the tissues will respond to repositioning. In a facelift, for example, residual filler in the cheeks, jowls, or nasolabial folds can affect how the skin and soft tissue drape after lifting — potentially leading to an unpredictable or suboptimal result.
In rhinoplasty, the stakes are even higher. Filler in or around the nose — whether placed to straighten the nasal bridge, lift the tip, or conceal a bump — can complicate surgical access and make it significantly harder to achieve the desired outcome. Filler left in the nasal tissue during surgery can also increase the risk of post-operative complications such as vascular compromise, which carries serious risks in this anatomically sensitive area.
Pre-Surgical Dissolving and Blepharoplasty
For patients planning blepharoplasty (eyelid surgery), tear trough filler is almost always required to be dissolved beforehand. The tear trough region is anatomically complex and delicate, with limited blood supply and close proximity to the eye itself. Residual filler in this area during surgery can obscure the surgical field, affect tissue behaviour, and increase the risk of complications. Ultrasound guided dissolving is particularly well suited to this area, as the imaging allows Dr Karwal to identify and precisely target filler in these very thin, sensitive tissues without disrupting surrounding structures.
How Far in Advance Should Filler Be Dissolved?
The timing of pre-surgical filler dissolving varies depending on the procedure, the quantity and location of filler, and the advice of the operating surgeon. As a general guide, most surgeons recommend that filler dissolving is carried out at least four to six weeks before the planned procedure. This allows time for the hyaluronidase to fully clear, for any post-dissolving swelling to settle, and for the surgeon to carry out a final assessment of the tissues in their natural state. Dr Karwal will liaise closely with your surgical team to ensure the timing is appropriate for your specific case.
The Advantage of Ultrasound Guidance for Pre-Surgical Dissolving
Pre-surgical dissolving is precisely the kind of complex, high-stakes scenario where ultrasound guidance offers the greatest advantage. In some patients, filler has been placed by multiple practitioners over many years, and its exact location may be unknown — even to the patient. Ultrasound scanning allows Dr Karwal to map every deposit of filler before treatment begins, ensuring nothing is missed. This is particularly valuable for surgical teams who need confidence that the tissue they will be operating on is entirely free of residual product.
The precision of ultrasound guided dissolving also means that the minimum effective amount of hyaluronidase is used, reducing recovery time and ensuring the tissues are in the best possible condition for surgery.
Who Is Ultrasound Guided Filler Dissolving For?
Ultrasound guided filler dissolving is particularly valuable in the following scenarios:
Patients who have had filler placed by multiple practitioners or whose filler history is unknown. Patients with old or migrated filler. Patients with filler placed in high-risk anatomical areas such as the nose, tear troughs, or around the eyes. Patients with complex multi-treatment histories who want clarity before proceeding. Patients who need filler removed prior to surgery such as a facelift or blepharoplasty. Patients experiencing or who have experienced a vascular occlusion requiring emergency dissolving.
Dr Karwal will assess your individual situation during a consultation to determine the most appropriate approach.
Benefits of Ultrasound Guided Dissolving
Fewer Sessions, Better Results
Because hyaluronidase is delivered precisely to the filler, treatment tends to be more efficient. Patients often need fewer sessions to achieve the desired result, with less product used per session — in contrast to a more generalised approach, which may require multiple rounds of treatment to dissolve all the filler effectively.
Reduced Risk of Side Effects
Delivering hyaluronidase with ultrasound guidance reduces the risk of over-treatment, accidental dissolution of desirable filler, and complications such as bruising or allergic reaction from excessive enzyme use. By using the minimum effective dose in the right location, Dr Karwal can achieve the best results with the least disruption.
Clarity on Complex Filler Histories
For patients who have had filler placed by multiple different practitioners — perhaps over many years — there can be real uncertainty about what is in their face and where. Ultrasound scanning provides clarity. Dr Karwal can build a clear picture of your current situation before any treatment begins, giving you informed, evidence-based options and complete peace of mind.
Safer Treatment in High-Risk Areas
Certain areas of the face — such as the nose, the tear troughs, and the area around the eyes — carry a higher risk of complications during both filler injections and dissolving. Ultrasound guidance allows Dr Karwal to navigate these areas with greater confidence, avoiding sensitive structures and reducing the risk of adverse events.
Ability to Monitor Treatment Progress
Ultrasound is not just useful before and during treatment — it can also be used to monitor the response to hyaluronidase. Dr Karwal can check whether the filler is dissolving as expected and whether blood flow appears to be returning to the affected area. This ongoing assessment means treatment can be adjusted in real time if needed.
Part 5: What to Expect at Your Ultrasound Guided Filler Dissolving Appointment
Step 1: Your Initial Consultation
Every ultrasound guided filler dissolving journey begins with a thorough consultation with Dr Karwal. During this appointment, Dr Karwal will take a detailed history of your previous filler treatments, discuss your current concerns and goals, and assess the treatment area. This is your opportunity to ask questions, share any worries, and understand exactly what your treatment will involve. You are under no obligation to proceed with treatment at the consultation stage.
Step 2: The Ultrasound Scan
Before any dissolving treatment begins, Dr Karwal will perform an ultrasound scan of the areas being treated. A small amount of gel is applied to the skin, and the ultrasound probe is moved gently across the surface. The scan is completely painless and takes just a few minutes per area. The images allow Dr Karwal to see precisely where the filler is located, at what depth, and in what quantity — forming the basis of a carefully personalised treatment plan.
Step 3: The Dissolving Treatment
Once the scan is complete and the treatment plan is agreed, Dr Karwal will administer hyaluronidase using fine needles or a cannula, guided by real-time ultrasound imaging. The number of injections required will depend on how much filler is present and how widely it is distributed. A topical anaesthetic cream can be applied beforehand to minimise discomfort.
Step 4: Immediately After Treatment
Following the hyaluronidase injections, there may be some temporary swelling, redness, and tenderness in the treated area. This is a normal response and typically settles within 24 to 48 hours. Dr Karwal will advise you on what to avoid in the immediate post-treatment period, including certain skincare products, exercise, and heat exposure.
Step 5: Follow-Up and Results
Hyaluronidase begins working quickly, but the full results of filler dissolving may take one to two weeks to become apparent as the filler breaks down and the tissue settles. Dr Karwal will schedule a follow-up appointment to assess the outcome and determine whether any further treatment is needed. Many patients are delighted with the results after a single session.
Part 6: Why Ultrasound Is the Gold Standard — and Why It Matters to You
The Evidence Base for Ultrasound in Aesthetic Medicine
The use of ultrasound in aesthetic medicine is supported by a growing and compelling body of evidence. Leading aesthetic bodies, professional organisations, and academic publications have all highlighted its role in reducing the risk of complications and improving outcomes in both routine filler treatments and emergency management. The technology is increasingly being recognised as the expected standard of care for complex cases.
Dr Karwal stays at the forefront of these developments, ensuring that patients at Karwal Aesthetics always receive care that is informed by the very latest clinical evidence and best practice.
Why More Practitioners Are Turning to Ultrasound
The UK aesthetics industry has been under increasing scrutiny in recent years, with widespread calls for higher standards of training, regulation, and patient safety. Ultrasound guidance represents one of the most significant advances in safe aesthetic practice — enabling practitioners to see what they are doing beneath the skin and dramatically reduce the risk of complications.
Today's patients are also more informed than ever. They research their treatments thoroughly, ask about qualifications and techniques, and expect evidence-based care. As patients understand the difference between a precise, imaging-guided approach and a more generalised one, demand for ultrasound guided filler dissolving continues to grow.
What to Look for When Choosing a Provider
Not every clinic offers ultrasound guided filler dissolving. It requires a specific combination of equipment, training, and experience — the practitioner must be skilled in both diagnostic ultrasound and the administration of hyaluronidase, and should ideally have a medical background that supports a thorough understanding of facial anatomy.
When researching providers, confirm that the practitioner has specific training in ultrasound imaging for aesthetic purposes, is medically qualified, and has experience in managing both routine and complex filler dissolving cases. Dr Karwal meets all of these criteria and has built a reputation for safe, expert practice at Karwal Aesthetics.
Prevention: The Importance of Choosing the Right Practitioner First Time
The risk of vascular occlusion and other serious filler complications is significantly reduced when treatments are carried out by a highly trained, medically qualified practitioner with a thorough knowledge of facial anatomy. Dr Karwal uses fine cannulas where appropriate, aspirates before injecting, and injects slowly and carefully to minimise risk at every stage.
While no injection is entirely risk-free, the standard of care at Karwal Aesthetics is designed to minimise your risk from the outset — and to be fully equipped to manage any complication that does arise, quickly and effectively.
Frequently Asked Questions
What is the Tyndall effect and can it be corrected?
The Tyndall effect is a bluish or greyish discolouration caused by hyaluronic acid filler placed too superficially under thin skin — most commonly in the tear trough or under-eye area. It is entirely treatable. Dr Karwal uses ultrasound guidance to precisely locate the superficially placed filler and dissolve it with hyaluronidase, restoring a natural appearance without disrupting surrounding tissue.
Do I need an allergy test before hyaluronidase treatment?
For planned, elective filler dissolving, allergy testing — either a patch test or intradermal test — may be recommended, particularly if you have known sensitivities or have not had hyaluronidase before. Dr Karwal will discuss your allergy history at your consultation and advise on whether testing is appropriate. In a genuine filler emergency, treatment cannot wait for testing — the risk of not acting immediately far outweighs the small risk of an allergic reaction, and Dr Karwal is fully equipped to manage reactions should they occur.
What is impaired capillary refill time and why does it matter?
Capillary refill time (CRT) is an assessment of how quickly blood returns to the skin after brief pressure is applied. In healthy tissue, colour returns within two seconds. An impaired or delayed CRT in a treatment area — even without obvious colour change — can be an early clinical sign of vascular occlusion. Dr Karwal assesses CRT as part of routine monitoring during and after filler treatments, which is one of the reasons that having a medically trained practitioner is so important.
I am having a facelift — do I need to dissolve my filler first?
In most cases, yes. Surgeons typically ask that dermal filler is dissolved before facial surgery such as a facelift, rhinoplasty, or blepharoplasty. Residual filler can affect surgical planning, tissue behaviour, and post-operative outcomes. Dr Karwal offers pre-surgical ultrasound guided dissolving and will work with your surgical team to ensure the timing and approach are right for your procedure.
Can I have dermal filler after surgery?
Yes, in many cases filler can be re-introduced after you have fully recovered from surgery. Your surgeon and Dr Karwal will advise on appropriate timing — typically a minimum of several months post-operatively, once all swelling has resolved and the surgical result has fully settled.
Can vascular occlusion be prevented entirely?
While it cannot be entirely eliminated as a risk, vascular occlusion is significantly less likely when treatment is carried out by an experienced, medically qualified practitioner who has a thorough understanding of facial anatomy. Careful technique, slow injection, and using fine cannulas where appropriate all reduce the risk.
Is hyaluronidase safe?
Yes. Hyaluronidase has a well-established safety profile and has been used in medical and aesthetic practice for many years. As with any injectable treatment, there is a small risk of allergic reaction, which Dr Karwal will discuss with you during your consultation.
How long does filler dissolving take to work?
Hyaluronidase begins working within minutes of injection. However, the full results of filler dissolving typically take one to two weeks to become apparent as the filler breaks down and the tissue settles.
How many sessions will I need?
Many patients achieve their desired result in a single ultrasound guided dissolving session. Because treatment is targeted and precise, it is often more efficient than standard dissolving. Dr Karwal will assess your individual case and give you a realistic expectation during your consultation.
Can I have filler again after dissolving?
Yes, in most cases. Dr Karwal will advise on an appropriate waiting period before any new filler is placed. Typically, a minimum of two to four weeks is recommended to allow the hyaluronidase to fully clear and for the tissue to settle.
What if my original filler was done somewhere else?
This makes no difference. Dr Karwal regularly treats patients whose filler was placed by other practitioners, including complex cases where the full filler history is not known. Ultrasound scanning is particularly valuable in these situations, as it allows Dr Karwal to see exactly what is present before treatment begins.
Is ultrasound guided dissolving available near me?
Ultrasound guided filler dissolving is not available at every aesthetic clinic. Many patients find that travelling a little further for this level of care is well worth it — particularly for complex cases, sensitive areas, or pre-surgical dissolving. Karwal Aesthetics offers this advanced treatment and welcomes patients from across the UK.
Book Your Consultation at Karwal Aesthetics
Dr Karwal is an expert in advanced aesthetic treatments, filler emergency management, and ultrasound guided filler dissolving. Whether you have concerns about existing filler, are experiencing symptoms that worry you, want filler removed before surgery, or simply want a professional assessment — Karwal Aesthetics is here to help.
Patient safety and confidence are at the heart of everything we do. From the very first consultation to your final follow-up appointment, you will be cared for with expertise, precision, and compassion.
Book your consultation with Dr Karwal today.
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