Pain occurs after a fever because the cerebral blood vessels dilate and cerebral blood flow increases in patients with fever and also in patients with fever, inflammation-causing factors in the blood circulation can produce pain and can cause pain in the central nervous system. In addition, some patients with fever can develop sleep inversions or have difficulty sleeping, which can also cause neuropathic pain. A few others are due to the occurrence of a central nervous system infection. If a patient has pain after a fever, he or she can be treated with symptomatic antipyretic and analgesic drugs, and the cause of the headache should be investigated, and then targeted medication should be given to prevent the condition from deteriorating.