always hiding it

Since ive been about 9 ive always picked at the skin on my fingers starting with my Thumbs.im 20 now and the fact that its been going on so long and im always so embarrassed of my bloody and scabbed fingers and the habit causes me a lot of pain. Little things like washing my hands or even eating French fries stings so bad. Ive been.able to stop a couple times but only when i feel absolutely relaxed. I just dont know what to do anymore.. I'm always ashamed of my hands or hiding them and im.usually so zoned out when im doing it. I know its triggered by stress but does anyone have any tips that have worked for them?