Many people will have hard nodules after vaccination. This is due to the local immune reaction caused by the components of the vaccine and the dissolved vaccine components, inflammatory cell infiltration, histiocyte and fibroblast proliferation, which are usually not a big problem and do not require disposal. If you feel uncomfortable with the nodules, you can use hot compresses as soon as possible after the nodules appear to promote their dissipation, and of course, you can also use drugs such as Xylitol to promote the absorption of the nodules.