I recommend that you do not manipulate the blisters. Your could cause an infection or worse. It's difficult to give you advice without actually examining you or having more information on your history. However, blisters can be caused from anything simple as skin irritation (tape, chaffing, etc) to something more serious as a burn, skin compromise, or a skin infection.Follow-up with your plastic surgeon, and he or she can guide you on treatment and therapy.
I would not open the blister. It will heal faster if left alone. Have your surgeon evaluate the are to see what caused the blister ie: tape, bra etc. Good luck. Donald R. Nunn MD Atlanta Plastic Surgeon