If there is a lump at the needle opening after the new crown vaccine, you can apply cold or hot compresses to reduce the swelling, and if necessary, go to a regular hospital in time for treatment. If the lump is less than 1.5 cm, it will be relieved on its own after a period of time without special treatment. If the lump is between 1.5 and 3 cm, cold compresses can be applied within 24 hours to reduce the swelling, and hot compresses can be applied after 24 hours to promote local blood circulation, so as to make the lump disappear. However, if the lumps are particularly large, it means that there is a serious infection, and you need to go to the hospital in time for treatment. After the vaccination, we should pay attention to observe whether there is any adverse reaction, and at the same time, avoid getting water on the vaccination site within three days.