My Female Normal has this same mark, but shes in deep shed and getting ready to get it off. She is used to rubbing around a lot during shed because for 3 years she was in a gigantic tank with extrememly low humidity.

It goes away over time, but that one looks pretty fresh, i would push some Neosporin without painkiller on the wound and let it heal up. As long as it doesn't get worse or spread, you should be fine.