thank you for your question. There are many people like yourself that might have the same concern.You were likely born with an underdeveloped muscle that draws the lower lip down ( depressor anguli oris muscle- DAOM). This is something you can read more about on line. There are ways to surgically transpose other muscles into this area to help achieve its function. However, the easiest and less invasive option would be to use Botox on your good side. In that way, both muscles would be inactivated and your smile would be symmetric.Best wishes!