BUMPS ON THE PENIS

hi i had a question about something that has been goin on on my penis. first of all i am a virgin and never had oral sex either. But i have been masterbating frequently some times with out washing my hands before. Recently i have discovered a few colorless bumps near the middle of my penis no itching or burning. Now one of them is a little bigger and is red with a white head like a pimple. the other are only there when my penis is ereccted. Is this serious or could it just be a rash?