How to quit a bad habit?

I have a really bad habit of picking the skin around my fingernails so badly that they bleed in multiple places. Every day I'm wearing at least three band aids and the skin around my nails looks disgusting. I've tried the bad tasting nail stuff but that didn't work. They look horrible and its so inconvenient to always have to wear bandaids. Please help!
How to quit a bad habit?
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