For A Couple Weeks Now I Have Had Some Patches

For a couple weeks now I have had some patches of skin that are very itchy and irritated on the shaft of my penis. I thought at first it was just raw skin and would heal in a couple days but it didn't. I have been treating it with some jock itch cream and it has seemed to get better, but not completely. I have only had two sexual partners in my life, one being almost two years ago, and the other being my current girlfriend. I only had sex with my first partner once and got checked for std's after and it came back negative. I have been having sex regularly with my girlfriend for about tow months now. She has been tested multiple times for std's and all have came back negative, so i don't think it could be and std. We recently started using some lubricant every once and a while during sex, and i started having these itchy red spots shortly after we started using the lube. We haven't used the lube in a while though and he spots haven't gone away, so I don't know if that has anything to do with it. What could it be?