I wear one of these pretty much 24/7. I like the chain style because I can hook my fingernails into the links and "pick" at the ring. I got it somewhat cheaper, though, from a souvenir shop on a beach vacation about two years ago.
Get yourself some sort of discreet fidget toy that you can keep with you all the time. I wear a spinner ring that I can dig my fingernails into (one of these), and it has helped immensely.