How to stop?

So I have a bad habit of biting my nails and biting the skin around my nails to the point i break skin and it bleeds and it hurts all the time lol I don’t know why and I always just try to stop but find myself doing it all the time ... I get my nails done a lot so it helps me so much cause my fingers will heal up but when my nails come off I’m back at it again (damn Daniel) but !!! I can’t get my nails done because of money . Soooo does anyone know how I can stop ? I know this is probably a dumb question . Lol my mom says it’s a stress thing .. but idk