Although both approaches are acceptable, there is greater chance of infection and injury to the chin muscles using the intraoral approach. I prefer the external incision. It is about a one inch incision placed near the chin crease and in most barely perceptible once healing has taken place.
My personal preference is the external incision. The infection rate is lower (the mouth is impossible to completely sterilize), and implant positioning tends to be more favorable than with the intraoral approach.
It is difficult to confirm online based on your photos, but you may benefit from a chin implant. To know for sure, I suggest beginning with an in-person consultation to discuss your options. During your initial examination, your #chin will be evaluated along with the neck and jawline. A weak...