Lower eyelid pain, redness and swelling may be caused by over-nighting, blepharitis, acute dacryocystitis and other reasons. 1. Staying up too late: long hours and lack of sleep can lead to eye fatigue, which can cause lower eyelid pain and redness and swelling. 2. Blepharitis: Blepharitis, also known as granuloma, is an acute suppurative inflammation of the eyelid glands, mostly caused by staphylococcal infections, which can manifest as pain, redness and swelling of the lower eyelid when it invades the glands of the lower eyelid. 3. Acute dacryocystitis: If the lower eyelid pain, redness and swelling are obvious, and the eyes also have symptoms such as congestion, tearing and purulent discharge, it may be acute dacryocystitis. Inflammation can extend to the eyelids, the root of the nose and cheeks, and in severe cases, systemic discomfort such as chills and fever can also occur. It is recommended that patients exclude physiological factors, go to the ophthalmology department of a regular hospital in time, and take targeted treatment under the guidance of a professional doctor.