Maybe I am going out of line here, but that just doesn't make sense and actually makes me laugh when i read that sentence: "And today while he was eating a mouse i accidently hit it with a piece of wood." LOL! Anyhow, if I understand correctly, your feeding live. Would it be a possibility that you fed live and it bit your snake rather then you hit your snake with a peice of wood? As stated by Jeff F. , their skin is really hard and you would really have to give him a good whack. Just a suggestion, no need to cover it up if this is what happens just learn from your mistakes
I would really like to know how you hit it with a peice of wood though.