Hi, the tip of my penis is red and there is what looks like a very small scab on it. There is no pain although there is a very slight burning sensation a few seconds after I urinate (though not during). I recently started some fairly rigorous exercise and I am trying to determine if it might be chaffing of the penis, or something more serious like an STD. When I woke up this morning the tip of my penis was moist, though I would hardly call it discharge because nothing was actually pouring out. There is no bad smell either, which I heard is also associated with STD's. What do you think? Thanks.