when i bend my nipples and my chest sink. can be fixed by going to gym?
A true crater or dish deformity is a problem. It can not be correct without some type of revision surgery. Sometimes it requires fat transfer, liposuction of the surrounding area for blending, excision of more glandular tissue or a combination. The gym will not help.
Probably not. It might ba able to be improved upon with further fine liposuction towards the "edges" in order to improve the contour. If the nipples are "stuck" down to the muscle that would be a harder fix.