I am only 22 yrs old and have sagging, deflated breasts. Is there any way to make themperky and round again?

I want to do this through exercise naturally. I went from a high C to a B back to a high C to a B then all the way to an A back to a B [from ages 16-22]. Now the top and inside area of my breasts are sagging and seem deflated almost, is there any way possible to fix this through exercise? I really don't want surgery at age 22...