I started having inverted nipples after i began puberty. So i had IN from 13-25 yrs of age. It changed after I decided to breast feed my 2nd child. First i wore breast shields (looks like suction cups) during the 2nd part of my pregnancy. The nurses in the hospital began working with him immediately after childbirth to help him to start sucking from that area to make the nipple come out so he could latch on. Well it worked & i breast fed successfully for 3 1/2 months. Only stopped by choice. 5yrs later, my nipples are still normal. once in a while if i wear a spandex fitting shirt to sleep overnight, i may wake up with one nipple inverted & then i have to pull the breast skin back to make it come out again. Hope this helps! FYI- Inverted Nipples are usually inherited so i've heard.