Penis - White spot, rather sore. Started on Thursday after attending the US Open.

[Riviera]

I was at the US Open this past Thursday and everything was going great.  Towards the end of the day I noticed that the tip of my penis started feeling really sore.  Just the top of the tip of my penis head and only soreness and a slight redness.  I've started noticing that urine/pre *** was being secreted and it doesn't burn at all or feel uncomfortable as long as nothing is rubbing the tip of my penis.

I'm thinking it might be due to my walking around all day in the warm day and only really stopping to sit down to watch a tee off or put or grab a bite to eat.  I was wearing boxer briefs and noticed when I took them off that there was a bit of red coloring, which I assumed was blood.  Now I haven't had sex in a few months and only received oral sex, but it was unprotected and the woman was HIV/STD neg.

Could this be a simple case of soreness and can treat it over the counter? I'll be making an appointment with my doctor on monday to verify it isn't an STD, but would like to calm my nerves down a bit.  Any help is greatly appreciated.