Confused and anxious.

I don't really know what's wrong with me, honestly. At this moment I have a relatively well sized scab on my knee from falling a few weeks ago. I've been picking at it for an hour and am at a point where it hurts to touch it, but there are still bits of scab on it surrounded by raw flesh and I feel like I'll explode if I don't get it off. It's definitely not a subconscious thing since when I think about doing it before I actually proceed I get excited about the fact that I have a scab to pick. What the heck? There are so many things wrong with me sometimes I don't know whether I'm just making these things up because i'm really masochist or if there's something seriously wrong. Blarg!