Redness and swelling of the middle corner under the right eye may be caused by mosquito bites, wheals and viral blepharitis. 1. Mosquito bites: mosquito bites in the middle corner of the right eye, there may be small bumps, redness, swelling and other symptoms in the middle corner of the right eye. 2. Eyelid swelling: acute suppurative inflammation of the eyelid, commonly caused by staphylococcal infection, in the right eye at the middle corner of the lower edge of the granuloma, there will be obvious redness and swelling. 3. Viral blepharitis: a type of eyelid skin damage caused by viral infections, manifested as blisters, papules, etc., redness and swelling around the eyes, burning sensation and other symptoms. When symptoms such as redness and swelling appear in the middle corner of the lower right eye, it is recommended to go to the hospital for examination and diagnosis in a timely manner, and follow the doctor’s instructions for standardized treatment.