How Can Red Bumps On The Penis Head After Having Unprotected Intercourse Be Treated?

I had unprotected sex with a girl about a week ago now, and last night I noteced multiple small red bumps on my penis head. I don t know if its an std or a yeast infection as I have no pain or itching whatsoever, and I havent been able to get ahold of the girl I had sex with. Is it possibe to have a an std such as herpes without the discomforting symptoms that occompany it?