Sensory loss in the breast or more specifically, the nipple-areolar, complex is an uncommon complication of breast augmentation, occurring in less than 1% of simple breast augmentation. This is more associated with excessively large implants, poor breast pocket dissection and excessive retraction, and the use of surgical incisions around the areolar to place the implant in. I typically place my implants through a tiny incision in the fold on the underside of the breast. Excessively large implants result in the nerves to the nipple/areolar being stretched, thus proper implant selection is very important.
Any nipple numbness that occurs after breast augmentation is temporary and will resolved in a few weeks to a few months. Very rarely is the loss of sensation permanent.
Breast augmentation is a relatively simple procedure but it is vital that you go to a certified plastic surgeon that will best advise you on the implant and technique of breast augmentation.
I hope this has been helpful!