Question

My child has a bump on their arm the size of a soybean, which appeared after receiving the hepatitis B vaccine. Initially, it was just a small bump that didn’t attract attention, but it later swelled into a lump. Now it looks like it has peeled off, revealing red, raw flesh that feels soft and seems to have pus inside, but it’s not clear. The baby doesn’t have any special reactions. What should I do? Do I need to see a doctor?

Answer

It is normal for red or dark red small nodules to appear at the injection site after vaccination. These nodules may gradually become red and swollen, with a small pustule forming in the center, which will burst on its own. The diameter does not exceed 0.5 millimeters, and after 2-3 weeks, the sore will scab over and eventually the scab will fall off, leaving a permanent scar, which is also known as a “scarlet bump.” However, if the vaccination technique is not standard and the needle is inserted into the fat layer, it may form a hard lump the size of a soybean. The solution for this situation is to use hot compresses, which can be continued for about a month, or apply slices of potato directly to the wound, which can help relieve the lump.