Many patients visit our clinic with concerns like:

“The filler has been injected for a while, and now it’s becoming more noticeable and protruding…”

“I want to correct the asymmetry caused by treatments at another clinic…”

 

Cases where fillers in the forehead or lips become unnaturally swollen are particularly common.

 

In such situations, we first perform a filler dissolving procedure (Hyaluronidase injection), then schedule a follow-up treatment to rebalance and refine the results.

 

This is because if the type of filler used at another clinic is unknown, re-injecting without dissolving the previous filler may result in mixing different fillers, which often leads to an unnatural outcome.

 

Additionally, when the filler is injected at different layers, achieving the desired design becomes difficult. Therefore, resetting the area is the best approach.

 

In this article, I will explain in detail the filler dissolving injection (Hyaluronidase) that we explain to our patients before their treatment.

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What Are the Ingredients in Filler Dissolving Injections?

 

🔹 Ingredients: Hyaluronidase
Over 90% of fillers are made by crosslinking hyaluronic acid with BDDE (a crosslinking agent).

To dissolve fillers, Hyaluronidase is used to break down the molecular structure of hyaluronic acid.

 

✅ Biphasic fillers (e.g., Restylane Kysse) are easier to dissolve compared to monophasic fillers.

 

Biphasic fillers have a more gel-like consistency, which allows Hyaluronidase to break them down more effectively, making the dissolving process faster and more efficient.

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Side Effects and Precautions of Hyaluronidase

 

The most common side effect of Hyaluronidase is an allergic reaction.

✔ The incidence is reported to be less than 1%, but
✔ Rarely, severe allergic reactions such as anaphylactic shock have been reported, so caution is necessary.

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🔹 Allergy Test Before Treatment
At our clinic, we perform an allergy skin test by injecting a small amount of the substance under the skin of the arm before the procedure. After confirming safety, we proceed with the use of Hyaluronidase.

 

⚠ However, if a small amount of Hyaluronidase is used, the risk of an allergic reaction is lower, and in such cases, the skin test may not be as significant.

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🔹 Be Aware of Delayed Allergic Reactions
Allergic reactions may not only occur immediately but can also develop as a delayed (Type IV) allergy, occurring 24 hours to several days after the treatment.

 

✅ If you notice any changes such as redness, swelling, itching, or difficulty breathing within 2-3 days after the treatment, it is important to consult a medical professional immediately.

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When Should Forehead Fillers Be Dissolved?

❶ When the Filler is Centered
Forehead fillers tend to shift towards the center due to muscle movement and gravity, causing the outer areas to lose volume first.

 

❌ If the center becomes overly swollen and results in an unnatural shape, it may need to be adjusted with Hyaluronidase.

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❷ When the Filler is Compressing Blood Vessels

 

⚠ If the forehead or around the nose turns dark red or black after the procedure, there may be a risk of vascular occlusion. In such cases, it’s important to seek immediate medical attention.

In the case of vascular occlusion after hyaluronic acid filler injection, prompt treatment with a filler dissolving injection is essential.

 

If not addressed quickly, there is a risk of skin necrosis, making swift action crucial.

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When Should Lip Fillers Be Dissolved?

❶ Over Time, Lip Fillers May Drop Due to Gravity
As time passes, lip fillers may shift downward due to gravity and flow toward the skin side. In this situation, filler removal takes priority over re-injection.

 

❷ If Lip Vascular Occlusion Occurs
If a vascular occlusion (blood flow disturbance) happens in the lips, it’s crucial to dissolve the filler immediately to prevent complications.

⚠ If the lips turn abnormally bluish or purple after the procedure, there may be a risk of necrosis due to vascular occlusion. In such cases, seek medical attention immediately.

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Frequently Asked Questions (FAQ)

 

Does Hyaluronidase also break down collagen?
→ No, the dermal collagen in the skin is not broken down by Hyaluronidase. It specifically targets and breaks down hyaluronic acid in fillers, not the collagen in the skin.

Degradation of porcine dermal connective tissue by coUagenase and hyaluronidase K.FRIEDMAN (1986)

 

Hyaluronidase only breaks down hyaluronic acid and does not affect the collagen fibers in the dermis, as proven by research.

 

✅ In fact, research has shown that when Hyaluronidase breaks down hyaluronic acid in the skin, it stimulates fibroblasts, promoting the regeneration of the extracellular matrix (ECM).

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In the case of vascular occlusion, should Hyaluronidase be injected directly into the blood vessel?

→ No, it is effective when injected near the blood vessel, not directly into it.

Hyaluronidase has high tissue permeability and can penetrate blood vessels. By injecting it near the blocked blood vessel and performing a gentle massage, it can be effective.

 

⚠ There is no need to directly inject it into the blood vessel using ultrasound, and intravenous injection has little to no effect.

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3. Will the filler continue to dissolve indefinitely after a Hyaluronidase injection?
→ No, the effects of Hyaluronidase are temporary.

 

Hyaluronidase has a short half-life and is almost completely broken down within about 1 hour.

 

Therefore, once injected, it does not continue to dissolve the filler permanently.

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✔ If side effects from fillers occur, it's important to inject Hyaluronidase as soon as possible.

 

✔ Hyaluronidase carries an allergy risk, so monitor your condition for 2-3 days after treatment and consult a medical professional if any unusual symptoms arise.

 

✔ Hyaluronidase does not break down dermal collagen and has a short half-life, so it does not remain in the body for long.

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I hope this has been helpful to all of you!

 

If you have any questions, feel free to leave a comment 😊

 

This was Dr. Won Daehan, the chief director!

 

Thank you for reading until the end!

 

📍 Primi Clinic
52 Seongsu-ilro, Seongdong-gu, Seoul, 3F (Primi Clinic)