My baby is 22 months and he is biting his lower lips almost every time and bit aggressive..what does this means and what to do

A. Hello ma’am I am sure your child is showing some kind of a discomfort by behaving like this but till the time you do not get your child examined personally by a doctor it’s very difficult to comment on it so maybe I like your child is having teething or some other issue into the mouth which is why your child is behaving like this