Have you tried a rubber band around your wrist? I'm so sorry I don't have more to offer you. But I know this sounds like it's connected to anxiety. And it helps a lot of people to wear a rubber band around their wrist and snap it when they feel an anxiety attack coming on. In the same way, snapping may be able to help you ward of the urge to pick. You could also make yourself go do something to keep your hands busy. One heck of an excuse to play LOTS of video games!
Your doctor may have more ideas. I wish I could help more, but I don't have experience in this area really. But someone does care. :)
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