Eating crayfish lip blisters may be caused by vitamin B2 deficiency, herpes, allergies and other reasons. 1. Vitamin B₂ deficiency: a large number of vitamin B2 deficiency is mainly due to insufficient intake, vesiculation, etc., which will lead to reflex dysfunction, blisters on the lips, dry and cracked lips and other symptoms. 2. Herpes: Herpes is mainly caused by the decline in immunity, consumption of spicy and stimulating food, allergic skin and other reasons, which will lead to the symptoms of blisters on the lips and oral ulcers. 3. Allergy: allergy is mainly caused by diet or inhalation of allergens, allergy patients will lead to small blisters on the lips, conjunctival congestion, chest tightness and other symptoms. The cause of blistering lips may also be lipitis, viral infections, etc. It is recommended that patients go to the hospital in time for examination and symptomatic treatment under the guidance of the doctor.