If pus develops after BCG vaccination, it is mostly normal. This is because normally after 2-3 weeks of BCG vaccination, small localized hard nodules will appear, which will then soften to form pustules or abscesses, after which the pustules will break down to form ulcers and scabs, which will fall off to form permanent scars called card scars. A tuberculin test can be done 3 months after vaccination and is normal. If it is caused by other vaccines, local infection is considered and local anti-inflammatory treatment can be given with 75% alcohol. If necessary, take your baby to a child health department or vaccination site for professional consultation and treatment, and do not squeeze it indiscriminately.