I'm obese. Will exercise or losing weight improve them or get worse?
Unfortunately, losing more weight will not improve the ptosis of your breasts. You will need a mastopexy (breast lift) to correct the ptosis. You can consider breast implants at the same time as your lift if you are looking for more volume but not necessary if you are happy with your size and just want more lift.
While a healthy diet and exercise is always encouraged it will make no improvement to the degree of breast ptosis. You can consider a full breast lift with or without implants to improve the overall shape. I've included a video that may be helpful.