Juvederm cleft chin injections. How long will it last?

It sounds like you need more Juvederm. What has happened is that the swelling from the actual injections has begun to subside, making it seem as though your Juvederm is going away. This can easily be treated with a touch up injection of Juvederm. When full volume for correction is achieved the results can last you anywhere from  9 months to 1 year.

It sounds like you will need to have more filler injected to get optimal results.  Swelling occurs after injections and usually subsides within 3-4 days.   A full treatment of that area should last you 6-12 months. 

Swelling from hyaluronic acids generally recedes after 3 days and the final result around two weeks.  From there it will continue to break down over the next 8 to 12 months depending on the individual.  It is possible that not enough filler, or not the right combination of fillers were used to give you optimum results.  Using Radiesse and a hyaluronic acid like Juvderem Ultra Plus  together can give the volume needed to smooth out the cleft.  Because the cleft is caused by incomplete fusion of the lower jaw bone, the indentation lies deep and needs considerable volume to fill the cleft. Cleft chins are inherited, considered normal and in some cases, attractive.

Some patients get less than an optimal duration of benefit from some fillers, while others get better than expected. i have found very good results with injections of the horizontal cleft in the chin using Juvederm horizontally and high up in the dermis. Belotero also works very well for very superficial lines.

I have used Juvederm quite a lot for filling the chin, and it tends to need a repeat or touch-up in less than a year, especially if you talk or chew alot.  It is possible that after having 2-3 treatments, the cumulative collagen stimulation will result in even longer lasting results too.

In my experience any form of HA that's injected into a site like this - Restylane or Juvederm - usually lasts about a year. Initially after injection an injected area will swell. Some people actually like this look. So if this is what you desired and wanted, you simply need more product added to achieve this long term. "This answer has been solicited without seeing this patient and
cannot be held as true medical advice, but only opinion. Seek in-person
treatment with a trained medical professional for appropriate care."