I have words engraved on my legs, but I don't remember writing it?

I'm a former self-harmer, but lately I've noticed that I have the words 'I DESERVE THIS' badly cut into my left leg, like with a razor. It's so neatly written and its my 'handwriting'. I haven't been drunk or anything lately? I thought it was just a strange pain I was having for days, and I haven't been sleeping much, like for 3 days.