What To Do For The Bump Below The Hole Of The Penis In Child?

My 7 year old son just came back from swim team and he is crying saying it stings when he pees. He has a small bump, like a single rsah bump just below the hole in his penis. I put some Lotrimin on it, thinking it might be a jock itch or yeast issue, but it isn t helping and he is pretty upset.