Disclaimer: these tips did work for me, but that doesn’t mean they will work for you. (I hope they do though). This is kinda my story about how I stopped picking at my skin.
I know this is something many people struggle with. I used to struggle with it too. At some point I used to pick on my nails all the time, or tearing of skin from the fingers. At some point it got so bad that my fingers would just start bleeding with every little movement.
But of course this had to stop, because it’s very unhealthy, and if anybody has skin like I did back then, they are prone to infections.
I tried polishing my nails with some bitter nail polish so I could stop biting them off when I was way younger. Don’t do that! It didn’t work for me. Whenever I wanted to eat something with my hands, it would taste like the nail polish. I couldn’t eat chips, popcorn, sandwiches or even pizza. I couldn’t eat ANYTHING that is supposed to be eaten with hands. When I was using that nail polish, I would starve myself for days, since everything tasted awful. I had stopped picking at my skin at the time, but I couldn’t eat! So it wasn’t an effective method. Plus, I would pick on my toes - literally - since I was basically addicted to tearing of skin! So that was an unsuccessful method. At some point I tried wearing gloves, but the gloves were really uncomfortable, so I couldn’t write down schoolwork and do everyday stuff with them. Plus, at some point of the day I would need to put of the gloves, obviously. Then I would start picking at my skin again. So that was an unsuccessful method too.
My mom was really worried, so she bought me a bunch of hand cream tubes, hand oils, and stuff like that. At that point, I was worried too, but not too much. Of course my hands were better than they were before, but I still was picking at my skin. What I did was apply hand cream 3-4 times a day, and I even got a manicure and pedicure. My nails hurt then, but it was fine, because after a couple of weeks after I tried not to pick on them, they were WAY better. I used olive oil to massage my fingers and toes. It promotes nail growth and faster healing. Here in Greece olive oil is super common to find, and it is extremely cheap. However in other countries it is not that easy to find olive oil. Coconut oil is a good alternative though! I believe it is easier to find.
Of course I still pick at my skin at times, but I try not to, especially with the coronavirus outbreak.
Now my skin looks way healthier and better! By the way, here is another tip; ask one of your roommates/family members to tell you to stop once they find you picking at your skin. It really helped me! And if you live alone, putting your hands in your pockets helps too!
I hope these tips work for you 
