little red bumps?

I danced with a girl at the club 5 days ago, got an erection while dancing and my penis was rubbing all over my underwear as it also rubbed against her. when i got home I noticed there was a red and irritated big spot, whithin a day it started to fade away but then little red bums showed up. no pain, they dont bother. it can however get a bit itchy for 2 seconds every now and then (not often). are these broken glands? or please tell me what these could be. should I worry?
also my ex gf after some guys she has had sex with recently, found out she had hpv as things showed up on her down there recently and ended up being hpv. i havent had intercourse sex with her for about 2 years now but had 'manual sex'  with her 7 months ago before these guys she had sex with and the guy she thinks transmitted her this and before her bumps started to show up. should I really worry that she probably had hpv before those guys even though her symtoms (symptoms) showed up soon after she had sex with that one guy?