The hard lumps from the quadruple vaccination are stimulated by the needles, and some hard lumps are formed because of the slow absorption of the vaccine locally. Don’t worry about the hard lumps after vaccination, you can use hot towels to apply hot compresses. Hot compresses can promote the blood circulation of the hard parts, accelerate the absorption of the medicine, and play the role of dissipating the hard lumps. After 24 hours of vaccination, you can touch the vaccination site to see if there are any hard lumps, so you can find them early and apply hot compresses quickly. If the hard lump is relatively large, you can use magnesium sulfate compresses on the hard knot.