Reddening refers to a situation where a woman has sex during her menstrual period which in turn leads to bleeding. This bleeding may be menstrual blood, or it may be caused by a cause of hymenal laceration, vaginal laceration, bleeding from the mucous membranes or bleeding from blood vessels. Symptoms of redness can manifest as vaginal bleeding and some women may also experience lower abdominal pain. Normally, women need to abstain from sex during menstruation and when there is vaginal bleeding, as it can easily lead to vaginal infection and upstream infection to the uterine cavity, which can lead to uterine infection or even pelvic infection. This may lead to gynecological diseases and even infertility in the future, affecting women’s health. Women must stop having sex after the red bump, and if necessary, they need to go to the hospital for examination and treatment.