W.H.
This happened to my son! I don't remember what age he was, I think around 9-10. It was puberty kicking in. He was very self-conscious about it and wore a Band-Aid over his nipple until it went away which cracked me up - better a Band-Aid rectangular bulge than a swollen/lumpy nipple bulge! His reasoning was if his shirt came up somehow and a classmate noticed, he could make up a wild story like a bear ripped my nipple off. My offering of why not say a bee stung you wasn't manly enough! His doctor should be a standup comedian - the two of them had quite the time thinking up "excuses"!