BCG vaccination is given to prevent tuberculosis in children. BCG is a vaccination used to prevent tuberculosis in children, and the vaccination gives children a specific resistance to tuberculosis. The reaction after BCG vaccination is different from the general preventive injection. Usually, about 3 weeks after vaccination, redness and swelling will appear at the vaccination site, which gradually softens in the middle and forms small white pustules, and pus will be discharged after the pustules break down. The whole process usually lasts for about 2 months. After BCG vaccination, the lymph nodes near the vaccination site will also swell, which is a normal reaction. As the vaccination site heals, the swollen lymph nodes will subside on their own, and you can use hot compresses to help them subside.