Harm of biting nails: there are many bacteria, which are easy to get sick, such as parasitic diseases, hepatitis and gastroenteritis. It affects the appearance, and it is difficult to recover after the nails are deformed. Mental illness, eating fingernails is a symptom of obsessive-compulsive disorder. If not corrected in time, it will affect mental health. To correct this small problem, you can try the following methods: wear rubber gloves on your fingers, which are used to count money. It's a little uncomfortable, but it's not serious. Apply warning nail polish to your nails, so that when you see the warning color, you will have a sense of not biting, and it will be good to form a habit over time. You can apply cool oil or wind oil essence to your fingers, which is harmless to your body, but whenever you want to bite your fingers, you will smell the irritating smell, thus giving up the idea of biting.