Why might i have a habit of biting my lower lip?

Overjet: Overjet (commonly referred to as overbite) is the horizontal distance the upper and lower front teeth are from one another. Many patients who have a moderate to severe overjet find that the lower lip fits easily into that space. As a child they learn to swallow that way, and it becomes a neuromuscular habit. It usually goes away with orthodontic correction.

Dr Bassman and another doctor agreed

Nervous habit: Most of the times it's just a habit or nervous habit. Sometimes it can be related to your bite if you have severe overjet.

Dr Bassman agreed

Your bite: Your bite may be contributing to your lip biting. See an orthodontist to see if they can help you with your problem.

Dr Bassman agreed

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