What will fix my weak chin? (photos)

With your degree of chin/jaw shortness, young age and lip incompetence, you would be best served with a sliding genioplasty for your chin augmentation. Moving the chin bone would provide the best long-term solution.

When patients have a weak chin, a Silastic chin implant is an excellent alternative to give projection to the chin to help with facial balance and proportions. Chin implants are manufactured in a variety of sizes and shapes, are inserted through a sub mental approach under local anesthesia as an outpatient procedure.

From your photos it appears you have asmall chin but without a physical examination and some imaging it's impossible to give an opinion sstonwhat would best treat your condition. Maybe as simple as a chin implant to as complicated as upper and lower jaw surgery as well as chin surgery. Consultation would be the best next step. Best of luckDr M 

Could be many reasons.  Either upper jaw grew too much down, lower jaw small or small chin. Need to be evaluated to see what is the best treatment.