Platysma muscles causing double chin or fat? (photo)

Localized fat under the chin can be present even if you are at a healthy weight. A clinical examination will determine if this is amenable to predictable correction. In younger patients, I frequently perform SmartLipo to this area with nice lasting improvements and little recovery time. Dr. Mosher

Based upon the photo you have a weak (receding) chin and maybe a bit of residual baby fat. A chin implant can be used to lengthen the chin (and jawline) thus taking up some of the slack in skin under the chin. Liposuction May or may not still be necessary to thin out the baby fat. Glad to help. 

It is best to examineyour chin area and feel for the fat.  Based on the picture and your age what you have is fat. Tumescent liposculpture with fine cannulas help this area tremendously.  In the past 10 years I have achieved amazing natural results with this technique.  The cost of this procedure is about $1000.

In someone who is 21 years of age, the issue is typically excess fat in the area under the chin as well as a weak chin that creates the double chin. The fat can be treated with conservative liposuction and the skin can be expected to contract after liposuction in most young people. A chin implant would also help lengthen your jawline and further sharpen the neckline as a result.Stephen Weber MD, FACSDenver Facial Plastic Surgeon

  A chin implant and chin liposuction would produce a nice improvement.Kenneth Hughes, MDLos Angeles, CA