I have gotten what looks to be a pimple on the shaft of my penis. It first started small with a white head but 4 or 5 days later it has gotten red inside of the pimple like it got popped but could not make its way out. It does hurt when I touch it. I have been with my girlfriend for over 2 years and it is the first time either of us have seen anything like this. What could it be? Should I try popping it as if it were a regular pimple? Im very confused and very worried. Thank you very much