There are some people who seem to get long term correction with fillers. The trauma of the injections may stimulate new collagen production so that the area slowly fills in. If there is filler still in there, it should have gone away as long as your doctor gave enough hyaluronidase to dissolve it. Juvederm can be difficult to dissolve, and often we need to use higher doses to eliminate. So may want to try once again with high dose. If the area is still elevated, may need to do some laser resurfacing on top to flatten.
Hyaluronidase is an enzyme that dissolves hyaluronic acid fillers. The dosage to dissolve Juvederm is higher than to dissolve Restylane, likely because of cross-link technique differences. Voluma takes extremely large doses of hyaluronidase to dissolve. I actually gave a lecture :The filler that lasts the longest is the filler in the wrong place. I think it must be a corollary to Murphy's law of unwanted consequences. You will get back to normal.
Over time, there have been studies that show that new collagen is formed through these injections. It doesn't sound like Hyaluronidase is needed but if you post a photo it might be easier to assess the situation. Best, Dr. Green
Hyaluronic acid fillers in general don't last past 18 to 24 months. The lasting effect of the filler is rated by its G prime. Juvederm has a lower G prime compared to other dermal fillers. Hyaluoronidase is usually the way to restore the area. I agree, your body may have produced collagen due to the filler causing an irregular finish.
The results of HA filler injection should go away 6-12 months after injections except for Voluma which lasts a bit longer in studies. Best, Dr. Emer.
Hi, an HA filler, like Juvederm, should be able to be dissolved with enough hyaluronidase. If the lump is still there, have the MD that did the injection try more hayaluronidase. In rare instances the injections could lead to localized bleeding that might result in scar tissue formation but even that would eventually flatten back done. It's far more likely that there's some Juvederm left.
Hope this helps.
Any HA filler should not lead to a permanent change. Juvederm will last about 9-12 months depending on where it was injected. If you have had hyaluronidase twice with no improvement then either you were underdosed or the Juvederm is gone. It is possible that the trauma from the original injection led to you creating new collagen (although creating so much that it has left you with an elevated area would not be very likely at all).
I'd recommend you consult with a facial plastic surgeon to better evaluate the area and determine what is the best way to restore your forehead.
I hope this helps and good luck.