I have a scratch on my hand, but I don't know where it came from, it is on the back of my hand...which doesn't make any sense at all I can't recall ever doing anything near anything with any type of protruding angle or bump that would allow me to scratch it there. It appeared out of no where and the interesting thing is it looks like a deep cut that has been healing for about a month or so...

Explanations?

I can only assume it happened when I was sleeping and whacked my hand on the wall or something.