There is no fastest solution for children’s mouth ulcers. It is recommended to actively treat them under the guidance of a doctor, including topical medication, oral medication, and other treatments. 1. Local medication: If the pain is more serious, you can choose pain-relieving drugs, including lidocaine gel, etc., but long-term use is not recommended. You can also use drugs that promote healing, such as ice boron powder. 2. Oral medication: If there is a vitamin deficiency, you can take oral vitamins, such as vitamin C, vitamin B, and so on. 3. Other treatments: laser irradiation can be used to help regenerate the mucous membrane and promote ulcer healing. If children’s mouth ulcers do not heal for a long time, it is recommended to consult a doctor in order to clarify the cause of the disease and standardize the treatment. All of the above medications should be used under the guidance of a doctor, avoid self-medication.