Personally, I think you have a nice chin and would not say that it is weak. It does not appear to me that surgery on your chin would enhance your appearance. If there is an aspect of your face that doesn't appeal to you, I would see a facial plastic surgeon or plastic surgeon for a consultation to discuss your concerns.
One would not say that you have a weak chin by normal facial standards. Whether you think a stronger chin would be more aesthetically pleasing is a different matter. If you want to see whether a stronger chin is more pleasing, have some computer imaging done.