A little head swelling after three months of radiotherapy for nasopharyngeal cancer may be related to the side effects of radiotherapy. Radiotherapy for nasopharyngeal cancer may cause expansion of cerebral blood vessels, resulting in metabolic abnormality of brain tissues, which is manifested as head swelling and pain. It is suggested that patients should pay attention to proper rest, ensure enough sleep, do not use brain for a long time, and pay attention to regular checkup to determine the growth of nasopharyngeal cancer and whether there is any problem of proximal metastasis or distant metastasis. However, it should be noted that high blood pressure, tumor brain metastasis, brain hemorrhage and other diseases may also cause head swelling and pain. It is recommended to consult regular hospitals to clarify the cause of the disease and receive standardized treatment under the guidance of doctors.