Double chin and square jaw from braces and TMJ. Would a chin implant help? (Photo)

Thank you for your picture. You would benefit from a comprehensive facial analysis.  Your asymmetry could be from your jaw and if so that needs to be addressed.  Your recessed chin could be due to  problems with your jaw joint allowing chin recession.  I could go on and on.  You just need to visit with a board certified plastic surgeon or facial plastic surgeon.

A cin implant and submental/jawline liposuction would provide the best correction to your double chin concerns.

A double chin is created from fat deposits in the neck, and liposuction can address removal of those fatty deposits. The photograph also demonstrates a weak chin profile, for which a chin implant can augment the chin for better facial balance and proportions. Chin implants are manufactured in a variety of sizes and shapes, are composed of Silastic and are inserted through a sub mental incision. For many examples of both procedures performed in combination, please see the video and the link below

It is not clear what is causing the double chin. It could be an anatomical variant and not fat. The chin is receding and narrow. This will respond to an augmentation with a chin implant. It may also detract from the double chin, somewhat.

The lower jaw is not well defined, which you can see in your profile view. If you augment the lower jawline, the relative fullness of the cheeks decreases and the "look" changes. Many examples can be seen on websites. The concept is not to reduce the cheeks but to increase the lower jawline definition.