Answer: Like other nervous habits, nail-biting tends to be unconscious. Your child may bite his nails for any number of reasons – curiosity, boredom, stress relief, habit, or imitation.
You can talk to ur child abt wat is making dem anxious...
If your child doesn't even know he's doing it, nagging and punishing him are pretty useless strategies. Even adults have a terrible time breaking habits like this.
In general, as long as your child's not hurting himself and doesn't seem overly stressed out, your best bet is to keep his fingernails neatly trimmed, remind him to wash his hands often, and try to keep your attention focused elsewhere. If you pressure him to stop, you'll just add to his stress and risk intensifying the behavior.
Make sure he has plenty of opportunity to run and play – outside, if possible – to burn off tension and nervous energy. Some kids find arts and crafts projects a good way to keep their hands busy and relax at the same time. For other kids, learning to play a musical instrument can be helpful.