Three days ago I had unprotected sex with a girl i had known for a pretty long time. Then the next night we had sex again only we used a condom this time. Tonight I looked at my penis and around the bottom of the shaft underneath, It seems that there is a pimple like bump on it. I popped it and a white pus, followed by clear/watery liquid came out. It seemed like a normal pimple however I never had a pimple there. I was afraid from not using a condom that I may have gotten an STD, but not sure if it may be just a pimple or an infection.