Large tooth pain in a 7 year old child is usually due to conditions such as periodontitis and pulpitis, which cause severe damage to the nerves in the gum location. It is necessary to take the child to the hospital for examination and timely root canal treatment. The more common clinical situation is toothache caused by dental caries in a seven-year-old child. In this case, you can take a partial dental radiograph of the tooth to see the specific carious condition of the tooth, and at the same time to check the condition of the permanent teeth below the decayed deciduous teeth. In the case of caries in the posterior cuspids and molars, we usually consider the use of fillings or root canals for the treatment of pain, as these teeth are still a long way from being replaced. If the symptoms of toothache, you can consider taking some analgesic drugs, clinically for seven-year-old children, you can generally consider the application of ibuprofen mix and other analgesic, relatively small side effects, but at the same time have antipyretic and analgesic effect. If you exclude physiological reasons, you should promptly consult a doctor to clarify the cause of the disease, and if necessary, carry out appropriate treatment.