The pain and swelling of the upper eyelid is considered to be related to mosquito bites, trauma, allergy, granuloma, dacryoadenitis and so on. 1. Mosquito bites: When some people are bitten by mosquitoes in the upper eyelid area, they are prone to pain and rash in the upper eyelid, accompanied by itching. 2. Trauma: some people can also be due to sharp object injury, chemical erosion, etc., resulting in upper eyelid injury, and upper eyelid pain, swelling phenomenon. Some patients also have eye pain, bleeding, vision loss and other symptoms. 3. Allergy: When the upper eyelid area comes into contact with allergic substances, such as dust mites, animal fur, etc., an allergic reaction will be induced, which will be manifested as pain, swelling and itching of the upper eyelid. 4. Granuloma: most patients are caused by staphylococcal infection. Typical symptoms of patients are redness and swelling of the affected area, pain, elevated skin temperature, increased ocular secretion, etc., which can be manifested as pain and swelling of the upper eyelid. 5. Dacryoadenitis: The disease can also cause upper eyelid pain and swelling in some patients. Dacryoadenitis is mainly related to infection and immune response, and the symptoms of patients include fever, pain, redness and swelling of the lacrimal gland, and increased secretion. It is recommended that people with sore and swollen upper eyelids consult a doctor in time in order to clarify the cause of the disease and then follow the doctor’s instructions for treatment.