The main reasons that cause four-month-old babies to bite their lower lips are hunger, psychological factors and teething.
1. Hunger: If a four-month-old baby feels hungry but is not fed in time, the baby may bite the lower lip to satisfy his desire to bite the nipple to eat.
2. Psychological factors: when four-month-old babies feel insecure, they will want to bite down on things, and if there is nothing else to bite, they will have to bite their lower lip.
3. Teething: Some babies have early eruption of milk teeth and may start teething in four months, when the milk teeth will stimulate the gums when they erupt, so the baby will bite the lower lip to grind teeth.
If your four-month-old baby bites his lower lip, you must go to the hospital in time to find out the cause of the problem and actively cooperate with the professional doctor’s treatment.