Some newborns will have a hard knot or what is called a bag on their arm after vaccination. For this situation, parents can take several measures from the following. The first is to apply a topical ointment to the child, as most hard knots on the arm are caused by local irritation, infection, etc. If there is redness and swelling, it is important to apply antibiotic ointment to the child in a timely manner. For example, parents can give their children Lincomycin lidocaine gel, or mupirocin ointment can be used. If there is no redness or swelling, parents only need to apply an ointment that activates blood circulation. Next, the child should be treated promptly against tuberculosis infection. If a child has a nodule on the arm caused by tuberculosis vaccination and the child has swollen axillary lymph nodes, the child should be given anti-tuberculosis drugs such as isoniazid and rifampin in a timely manner.