A couple of weeks ago my girlfriend and I were having sex without a condom. Neither of us have STI's. My penis began to burn a little and when we stopped, i notice that two big lumps were developing on the underside of my penis. It really freaked me out, but the swelling went down after a couple of hours. Since then, I have noticed that the vein on my ride side of my penis gets really big sometimes and the skin on the bottom of my penis gets irritated and dry and red from time to time. I don't know what to think of any of this. Anyone have any idea?