After the vaccination, if there is redness and swelling of the pinhole, it is likely that the pinhole site is infected. You can use hot towels to apply external compresses, which can quickly eliminate the symptoms of redness and swelling, and you can also take anti-inflammatory drugs orally at the same time, such as erythromycin granules, which is good for relieving the inflammation of the pinhole site. Through careful treatment, the symptoms of pinhole redness and swelling can be relieved. However, if the symptoms continue to worsen, it is important to treat them with an intravenous drip of anti-inflammatory drugs. During this period, the child’s body temperature should be carefully observed. If fever occurs, it is likely to be caused by a more serious infection. It is important to go to the hospital and follow the doctor’s instructions to avoid localized suppuration and necrosis. Local skin, if there is an open wound, should also be promptly sterilized and covered with sterile gauze.