Perineal swelling and pain may be caused by acute injury, inflammatory stimulation, vestibular cyst, allergic factors and so on. 1. Acute injury: such as riding injury or external impact, may lead to localized damage to the labia, causing symptoms of perineal swelling, accompanied by pain, and in severe cases, may also lead to localized bleeding. 2. Inflammatory stimulation: such as vulvovaginitis or vaginitis, as the perineum will be stimulated by inflammatory substances, which may lead to perineal swelling and pain, accompanied by vaginal itching, vulvar itching and other symptoms, and in serious cases, it is also easy to induce other infectious diseases of the reproductive system, such as cervicitis, pelvic inflammatory disease, and so on. 3. Vestibular cyst: It may cause swelling, pain, burning sensation and other symptoms in the perineum area. The symptoms of pain may worsen during sexual intercourse. 4. Allergic factors: localized exposure of the vulva to certain allergic substances leads to edema of the perineum, causing swelling of the perineum, and there may also be obvious itching symptoms. Therefore, when women find that the perineum is swollen and painful, it is recommended that they consult a doctor in time, complete the relevant examinations and actively deal with it under the guidance of specialists.