The nipple graft healing depends on the blood supply from underneath. Commonly, the top layer sloughs off, with fresh tissue underneath. Follow your plastic surgeon's wound care instructions. In the healing phase short-term, I advise patients to keep the nipple grafts moisturized. For long term...
Transitioning is not a requisite for top surgery. In my practice, I see cis hetero women and cis lesbian women who request top surgery. Some women prefer not to deal with breasts. There are many reasons for this including athletic pursuits, fear of cancer, "do not relate to my breasts",...