I've peen picking at the skin around my fingernails for years. It's not as bad as it used to be, but can still get pretty ugly when I get incredibly anxious. Yes, this type of condition is a form of self-harm, but it is more associated with anxiety disorders and stress than anything else, especially if it feels like more of a compulsion.
I've tried a few things to keep me from picking, such as placing small band aids around the places I pick most at (which for me are my thumbs) to discourage picking. I also try to just keep my hands busy in general when I am feeling an urge, such as typing, cleaning, writing, etc.
If you haven't already tried it, there are medications out there to help with this certain thing, although I am unfamiliar with the names of them. I would talk to a professional about it if you are having extreme problems with it or if it is keeping you from completing day to day tasks.
Hope that helps some! You're definitely not alone with this problem. Take care.