If you look carefully at your face, the entire left side is slightly underdeveloped or hypoplastic. This is seen by a lower eyebrow, inferiorly positioned eyeball, smaller cheek, thinner soft tissues and shorter jaw from chin back to the jaw angles. The jaw asymmetry in particular is magnified when you smile as the soft tissue of the chin is pulled back and deviates to the weaker or less developed side. There are a variety of facial asymmetry procedures that can be done from the eyebrow down to the jawline/chin. What you would do depends on how much of the facial asymmetry bothers you and what asymmetry location is most disturbing. The chin/jawline is the most obvious to you and this can be treated by a sliding genioplasty to move the bony chin over to the midline possibly combined with a small jaw angle implant in the back.