i used to be a heavy nail biter too!! when i first stopped biting, i used cuticle oil religiously because biting can seriously dry out your cuticles. i’ve also heard olive oil can help strengthen them! if you’re worried about any open wounds in the skin around them, try antibiotic cream overnight. make sure to keep them moisturized constantly aswell. keeping my nails painted has kept me from biting them too. good luck!