Post mastectomy op - possible necrosis nipple which seemingly continues to fight - is this normal? (photo)

The purple coloured skin had materialised almost immediately after surgery, was swollen and numb...we thought I may have necrosis and could lose the nipple. However, 5 days later, the nipple is still purple, warm and the sensations have returned. Whilst this is all very positive... as it seemed my nipple would most likely die, we now seem to be defying all odds! Is this normal? Could this be icshemia? My breast's are small following my mastectomy, how long until the second procedure can happen?