A swollen mouth after brushing your teeth can be caused by allergies or it can be related to trauma caused by external forces. An ingredient in the toothpaste may cause an allergy that leads to swollen lips. You need to stop using the allergenic toothpaste immediately and take oral desensitizing medication to relieve the symptoms. Brushing your teeth with too much force can also cause soft tissue swelling, which does not require special treatment and can be relieved on its own. In addition, lip inflammation or dental inflammation triggered by interstitial infection, can also lead to swelling of the mouth, need to carry out appropriate symptomatic treatment to relieve. Therefore, the swelling of the mouth after brushing teeth is mostly seen in allergic reactions, but also may be related to trauma triggered by external forces or lip inflammation. Prompt medical attention in the dentist is required. Medications should be used under the guidance of a physician.