Swelling and itching after the third vaccination is abnormal and is an adverse reaction, which can be treated with localized hot compresses and other physiotherapy.
After the third vaccination, some people may experience similar adverse reactions, including redness and swelling at the vaccination site, due to allergy to the vaccine components. These reactions are limited and usually resolve spontaneously.
Physical therapy such as localized hot compresses can be used to accelerate blood circulation and promote swelling, which can usually be relieved within 1 week.
However, if these symptoms continue to worsen, it is necessary to consult a doctor for blood tests and secretion cultures to determine whether there is a co-infection, so as to take targeted anti-infection treatment.