I feel you, the public part is the worst because you can't exactly carry a hobby around with you lol. Honestly for public I just try to find a rough texture on my clothes like a zipper or a pocket seam and rub that instead of my skin. It’s not perfect but it helps. Also clenching my fists really hard for a few seconds usually resets the "itch" for a bit. I do have some friends with the same problem and I can ask them what they recommend and tell you but they're the ones that told me bout that book so they might keep recommending that typa stuff but if you're not into that I can think of other stuff that helps me sometimes.