How do I stop biting my nails im 14 and its just a habit and i cant stop?

My mom bought me some nail polish that's supposed to stop nail biting that is named thumb something?????? That didn't work but i remember her putting one on my nails that was green liquid that had cactus or something and i forget what it was does anyone know what to do but some really good tips for it Please and something that will actually stop me FOR GOOD!