The tip of my penis was hurting a bit by contact basically just with my underwear. I'm not circumcised. When I checked my penis I noticed that the side of my urethra opening on the tip of my penis was swollen and reddish. It looked more like inflammation than a blister to be honest, but when I touched it a white fluid came out, it looked like pus. Now it's not swollen anymore (10 min later) and it really doesn't hurt even when I touch it. What could it be? Thank you in advance