What helps lip biting when nervous?

Attend / Substitute: You have to notice when you are doing it. Ideally try to notice what the feelings or thoughts are that precede it. Usually to pay attention to something it helps to track it. A log on your cell phone or on a piece of paper. Time, thought, emotion. Then try to substitute something else - when you feel the urge perhaps say the word "relax" to yourself and imagine yourself someplace relaxing.

Mental strength: This is a habit that you will have to try to stop. I know it will be difficult at first but you can be successful. When you get nervous, try to distract your self with another activity or pause for a few seconds and relax. Good luck.

Habit: It is a para-functional habit, that may have many causes, especially stress. Need to stop.