Tic scars are usually BCG vaccine. The BCG vaccine, which prevents and controls tuberculosis, is a live attenuated vaccine that has been artificially grown. Vaccination enhances macrophage activity, resulting in specific resistance. The main target of BCG vaccination is newborn infants and young children, usually within 24~48 hours after birth. Hard knots the size of peanuts will appear at the site of vaccination in 2~3 weeks, and as the hard knots gradually soften and break into scabs, tic scars will be produced. BCG vaccination is important for the healthy growth of newborn infants and children. Clinically, BCG vaccine is often used as an adjunctive treatment for asthmatic bronchitis and tumors. BCG vaccine is a free vaccine, and citizens are obliged to be vaccinated.