Redness and swelling at the site of the second 9-valent human papillomavirus vaccination, the symptoms of milder redness and swelling can be sterilized using iodine povidone. Localized redness and swelling at the vaccination site after the second dose of HPV vaccine is usually not a big problem. The reason for the redness and swelling at the second vaccination site may be due to the local antigen-antibody reaction that occurs when the vaccine is administered, which is a normal phenomenon, and it is sufficient to wait for it to subside on its own. Because the vaccine is a live attenuated vaccine or a vaccine with low toxicity, it usually does not cause serious reactions to the human body, but it should be noted that if the skin is still red and swollen after a week and accompanied by fever symptoms, it is recommended to consult a doctor as soon as possible for a clear diagnosis and targeted treatment.