How to stop biting my cuticles?

It's a nervous habit whenever I'm stressed, however, I'm in pre-medical, so I'm nearly always stressed, which is why my hands look like I stick them in a blender. I need a way to stop biting them, or something to dip them in so they regenerate faster. I allowed one finger to heal, and I never bit it again, so it seems I only need them to not already be bitten in order to break my habit, but I can't just quit cold turkey, I've tried before and it didn't work.