What should I do if my lower eyelid becomes red and swollen after a mosquito bite?

　　Swelling and redness of the lower eyelid after a mosquito bite are usually caused by local skin allergy and inflammatory reactions triggered by toxins, leading to insect bite dermatitis. Symptoms can be improved through cold compresses, topical ointments, oral medications, traditional Chinese medicine (TCM), or sublingual administration of polyvalent insect antigens.

　　1. Cold Compress

　　Apply a cold towel to the swollen area to promote vasoconstriction of the subcutaneous capillaries, helping to relieve swelling, discomfort, and itching.

　　2. Topical Ointments

　　If the redness and swelling are extensive and obvious, topical application of medications such as mometasone furoate gel, mupirocin ointment, or erythromycin ointment may help reduce inflammation, alleviate swelling, and promote recovery.

　　3. Oral Medications

　　If the above methods fail to provide sufficient relief, oral antiallergic drugs should be taken under medical supervision. Commonly used medications include cetirizine hydrochloride tablets, loratadine tablets, and chlorpheniramine maleate tablets, which inhibit histamine release to reduce inflammation and relieve symptoms.

　　4. Traditional Chinese Medicine (TCM) Treatment

　　Under the guidance of a qualified TCM practitioner, proprietary Chinese medicines such as Funing Granules or Jingfu Itch-Relieving Granules may be used to clear internal heat and relieve itching, thereby improving the condition.

　　5. Sublingual Administration of Polyvalent Insect Antigens

　　If such reactions frequently occur after insect bites, it is recommended to consult a doctor about sublingual administration of polyvalent insect antigens. This treatment continuously stimulates the immune system, reducing sensitivity to insect toxins and decreasing the frequency of future episodes.

　　During treatment, avoid frequent scratching or rubbing the eyelid with hands, as this may worsen swelling and itching or lead to infection. Seek timely evaluation and treatment at a hospital dermatology department.