If the skin is red, swollen and itchy after vaccination, it is recommended to go to the hospital to assess whether the redness, swelling and itching is an allergic reaction or an infection at the injection site, and then deal with it accordingly. If the redness, swelling and itching is caused by allergic reaction, you can use weak hormone ointment, such as mometasone furoate ointment, trimethoprim ointment, with oral second-generation antihistamines, such as loratadine; if the allergic reaction is more serious, you need to use short-term systematic use of glucocorticosteroids, such as prednisone. Redness, swelling and itching gradually aggravate, and local pressure pain is positive, most of them are caused by bacterial infection, which need to apply antibiotic ointment externally, and use broad-spectrum antibiotics systematically if necessary, such as amoxicillin (if you are not allergic to the drug) and cephalosporin. If the inflammation persists for a week without relief under the premise of regular anti-infective treatment, it is necessary to take a culture of the secretion fluid from the affected area to evaluate whether it is a special type of bacterial infection.