Probably got pregnant. No condition can change a woman's nipple like that. With pregnancy, the breast normally enlarges and it persists until the baby stops feeding, then it goes back to its original size. The nipple color though, it'll remain for a lifetime, sort of like a trophy. Some guys would get turned off with this. For me, this is how I know when a MILF really is a MILF and not just some single whore in her 30's or 40's.