Any surgery on the breast can result in the breast and/or nipple being overly sensitive or not sensitive enough. This change can vary in degree and may be temporary or permanent. It may affect comfort while nursing or sexual response.
During the healing process, you may feel numb, or overly sensitive, or both. This usually resolves with time. It is important to remember that it can take up to one year, possibly two, for sensation to return after breast augmentation surgery. The majority of women seem to get sensation back in a much shorter amount of time. Your sensation after surgery may be the same as it was prior to surgery, or you may be more sensitive or less sensitive. It is impossible to predict how your body will react after surgery.
Changes in Sensation -- by Dr. Daniel Shapiro