Thanks everybody. It doesn't seem to be hurting him any, he doesn't care if you touch it. I haven't seen him urinate lately, so I'm a little worried about that. I looked him in the barn for most of the day and I still haven't seen any urine.

I emailed my teacher at school (she teaches all the animal classes and equine classes) and she is also my riding instructor in the summer. Hopefully she'll get back to me, and know what it is. If not, guess I'll have to wait until Monday/ Tuesday when the vet sees him.