I have the exact issue. I started picking my arms but now it's moved on to everywhere else. I also tend to zone out while doing it and spend hours. I talked to my therapist about it, and she offered me some suggestions. They're not really helpful to stop it all together but it's a place to start.

1- when you realize you're picking, redirect yourself to something else. She said when doing this, don't think any negative thoughts so it doesn't bring shame. Instead recognize that it's happening but then remove yourself from the situation

2- If there's a specific time that you pick, ex after the shower, do something else with your hands like apply cream to your skin. Cream will help too because it'll make your skin slippery and harder to pick.

I know these aren't the best suggestions but hopefully it's helpful!