How long after mastopexy would you see signs of necrosis on nipple, if you were to get it?

You would notice this within 1-2 days from surgery.  The nipple/areola would start to darken and scab.  It may only be partial necrosis.  If you are concerned see your plastic surgeon immediately. 

Thank you for your question. Necrosis of the nipple can take place as soon as the next day to a week post-operatively.  

Hi. If there is a problem with nipple and areola perfusion (blood getting in and out) it may become obvious within hours of the surgery, however, it may take a few days to become completely evident and demarcate. best to raise any concerns with your plastic surgery early rather than later!