What is the sudden red acne on the face?

A lot of small red pimples suddenly appeared on the face. If accompanied by itching symptoms, it may be caused by contact with allergens. Therefore, the cause of allergy should be clarified first, and then symptomatic treatment should be carried out after removing the cause. If accompanied by itching, antipruritic ointment can be applied externally, such as mometasone furoate cream, calamine lotion, etc.