This has been happening for months now here is my story. On my back where the 'butt crack' area is i get this bump as big and round as a small marble and its full of blood. I have a hard time sitting down. When i change my boxer there is blood left on it because of the bump and after a week or so it goes away. I have problem sitting down and something walking. What is going on with my body.......

here was something i found that might help described it

For about two months now I've had this 'rash' between my butt cheeks (on the cheek itself, not anus) that goes away, but comes back. It's extremely itchy at times and I've used hydrocortisone to ease that a little and as well, used Zinc Oxyide (diaper rash forumula) thinking that moisture was the problem. On top of that, I think I may scratch it at night not thinking about it which causes it to bleed. I've actually found that the best relief is soap and water, keep it dry and NO lotions at all and I do my BEST to try to not scratch it, and it seems to 'dry up' and go away.

What confused me recently, is that yesterday, it was fine, this morning I woke up and it was red and very moist... probably a 3" x 2" patch. It's almost like the skin is 'broken', raw - sore and moist. If I put tissue down there and leave it for about an hour, it will be soaked. Like I said, this has been going on and off for a couple months. I was think of 'how' can this just happen overnight and it dawned on me that it might be herpes. I can't think of any other skin infliction that just pops up like that, then dries up and goes away.