Redness, swelling and hardness after Pentavalent vaccination are commonly caused by normal vaccine reactions or localized infections. It can be treated with medication or hot compresses. 1. Normal vaccine reaction: Because DPT is a biological product, it is a foreign stimulus to the body, which will cause local or systemic stimulation reaction, such as redness, swelling and hard lumps. Generally no special treatment is needed, it can gradually subside after 1-3 days, or you can use a clean towel to apply hot compresses. 2. Local infection: because after vaccination, the wound contact with water or contaminated items are not cleaned up in time, resulting in bacterial invasion and local inflammatory reaction, generally in addition to redness and swelling, local heat, pain and even pus, can be under the guidance of the doctor medication applied locally for treatment. If not treated in time may lead to the progression of the disease, causing generalized fever and other symptoms. If the above symptoms occur, consult a professional pediatrician in time and standardize the treatment under his/her guidance.