I personally don't know the answer to this but I will try to find something about it on the internet and let you know.

If it's only a reddish mark I'd say it's just an irritation that will go away after a few days... I had the same thing happen to me and kinda panicked in the beginning even though I know my gf is STD/infection free. I think it was due to a lack of lubrification. We went directly to intercourse that night without any foreplay and didn't use any lubricant...

Your case is different but like I said if his irritation matches the description of the one I wrote about then he shouldn't worry too much about it. It only lasted about 3 days for me and didn't stop me from having sex several times during these 3 days. I just used plenty of lubcrication...

yeah, you could of given it to him. it is possible to spread ( i gave it to my husband) they suggest men take oral medication to make it go away, that or he can use vaginal cream on his penis..