Documenting half healed scabs

I'm not a wound nurse, I'm a private duty nurse and noticed my patient had a very large scab over his shin bone. He said he scrapped it the other day. It's for the most part completely covering the open skin, but there are a few open areas where it must have been picked off or scraped off by other actions.

I have absolutely no idea how to document it. All I said in my notes was that a large scab was noted on the left lower extremity over the tibia and that no s/s of infection were present.