Nail biters are usually on a quest for order. If there is even the tiniest bit of skin or nail plate that is ragged, torn or 'sticking up', the first place that finger goes is in the mouth. You can try to break the habit by making a series of appointments with a good manicurist. She can help to get rid of the 'bits' of skin and nail that you bite, and give you some good Home Care recommendations.