Redness, swelling and hard lumps after baby vaccination can usually recover on their own in 1~2 days, and general measures can be taken during this period, which is conducive to their subsidence. When the local redness, swelling and hard lumps appear after baby vaccination, it is a common adverse reaction after vaccination, usually 1~2 days later can recover by itself, parents do not need to worry too much. During this period, you can use hot towels to apply warm compresses to promote blood circulation. In addition, magnesium sulfate can also be used as a topical compress under the guidance of a doctor, which will help the redness, swelling and hardness to subside to a certain extent. Usually, it is recommended to pay attention to the care of the vaccination site after vaccination, and avoid touching water for 1~2 days to prevent infection. If the redness, swelling and hardness of the baby after vaccination exists for a long time, or if the redness and swelling range is enlarged, or there are signs of aggravation such as ulceration, then you need to go to the hospital in time to avoid delays.