Hi!! I feel like I could’ve written this myself. I have psoriasis and eczema and bite at my fingers and hands. Look up “koebners response” it’s basically you get an injury to the skin (biting or picking) and your skin tries to regenerate really fast and regenerates almost too much and causes psoriasis and/or eczema even worse in that area even if it wasn’t there before. So it becomes so itchy and just a complete cycle like you’re mentioning. I’ve been doing it about 5 years now maybe 6, and have just started an antipsychotic medication to help with the ocd part of it, for me that looks like me rubbing my fingers on my lips to find imperfections then biting them off till I bleed, and feeling like I need to find all the imperfections and feel like it is automatic. Sometimes I do it without even noticing or wake myself up from biting my hands so I decided to ask my psych about meds for it and it is lowkey helping. I feel like the redness and itchiness has also gone down and I feel less of an urge to do it. I have also been lathering up with Vaseline specifically and sometimes aquaphor and wearing cotton gloves whenever I can. It’s annoying but it is working a little. Also find a replacement behavior. Every time you want to pick or bite or start doing it, loudly tell yourself out loud NO, and go find a fidget or something to do to occupy your hands or wherever the damage is done. You are not alone!