Hidden pain in the lower part of the body after menstruation may be related to trauma, allergy caused by foreign body stimulation, inflammation and infection, endometriosis and so on. 1. Trauma: If you fall down accidentally before or after menstruation, and your vulva collides with a hard object, you may have a vulvar straddle injury, which will cause a dull pain at the injury site, that is to say, a vague pain in the lower part of the body. At this time, you can apply cold compresses to the injured area, and then use red tablets, blood circulation tablets and other medicines to relieve pain and treat the injury. 2. Allergy caused by foreign object stimulation: If there is untimely change of underwear or allergy to sanitary napkins during menstruation, it may stimulate the vulva, leading to allergy or causing vulvar inflammation and local itching or pain. Generally, anti-allergy drugs such as oral loratadine tablets can be taken to treat and relieve vulvar pain. 3. Inflammatory infections: Due to the discharge of menstrual tissues, the natural defense function of the vagina is affected, and vaginal inflammation is prone to occur. The main symptoms of vaginitis are vaginal itching and increased secretions. Clinically, bacterial vaginitis is common, and can be treated with localized metronidazole and oral metronidazole or tinidazole. 4. Endometriosis: It can lead to bleeding before and after menstruation or dribbling menstruation, often manifested as lower abdominal pain, which lasts throughout the menstrual period, and the pain can radiate to the perineum of the body. Clinically, the symptoms can be relieved by taking sex hormone drugs such as norethindrone and medroxyprogesterone to inhibit ovulation. Severe symptoms can be treated through surgery, it is recommended that when there is a hidden pain in the lower part of the body after menstruation, you should go to the hospital for examination and treatment under the guidance of the doctor, the use of specific drugs need to follow the doctor’s instructions.