Redness under peehole?!

I've noticed that on the underside of my penis, just under my pee hole, it is red. It does not hurt at all, I can't really feel any difference, but it looks very red, especially after I masturbate. I haven't had sex since last October and I wore a condom so I don't think it's an STD. I do have sensitive skin that often dries in the winter so it could be that. I masturbate often I guess, I don't have a regular routine. Sometimes I'll masturbate twice in one day, sometimes I'll go four days without any masturbation at all, but after masturbation is when my penis looks it's worst. I'm just a little confused as to whats wrong. Is this normal? Maybe just some blood vessels close to my skin or something? Anyway thanks for you're help.