If your baby’s lower lip suddenly appears to be swollen, two factors are usually considered. The first thing to consider is the allergy factor, you need to pay attention to the baby recently eat, contact with things inside there is no easy to allergic to food or goods, if necessary, you can give the baby to check the allergens, blood routine to determine whether there are allergic substances. As long as the allergens are clearly identified and the baby is not exposed to them, the edema will subside naturally in the later stages. The second thing is to pay attention to the baby’s lips whether there is trauma, if there is local trauma in this area, because the skin mucous membrane is relatively fine, so there may be localized swelling, so you need to analyze the specific causes according to the specific circumstances of the baby.