I do a lot of this same stuff. My worst thing is I'm always picking at the skin along my thumb nail, with my index finger. I've done it so long now, that even when it heals there's a noticeable dent in my thumb where I've picked really deep into the meat.

These used to get infected all the time, but I've learned to put peroxide on them all the time now. I hate any kind of topical creams or anything like that with a passion, so I don't pick at them when they're still peroxide covered. Kind of using a phobia against a compulsion lol. Anyway, maybe that'll help someone else.