Mouth ulcers sprayed watermelon cream but swollen, may be in the acute stage of the disease, drug allergies, bacterial infections and other reasons, should be timely consultation to identify the cause of the disease. 1. The condition is in the acute stage: If the mouth ulcer is in the acute stage of the condition, after using the watermelon cream, the symptoms may not be obvious, the self-perception of swelling. 2. Drug allergy: watermelon cream has the effect of cooling and pain relief, but if you use too much, it may cause allergic reactions, resulting in swelling after using the drug instead. 3. Bacterial infection: Mouth ulcers in the spray watermelon cream treatment period, and the emergence of bacterial infection, can lead to worsening of mouth ulcers, swelling, pain, breakthroughs and so on. Mouth ulcers sprayed watermelon cream instead of becoming swollen, there may be other reasons, it is recommended that patients are advised to consult a doctor in a timely manner, please ask the doctor to clarify the specific causes, if necessary, the appropriate treatment, the use of drugs need to follow the doctor’s instructions.