The most common clinical cause of swelling and pain in the vulva is local inflammation, such as vulvar boils, which can be seen as red papules that protrude from the skin surface and are painful when touched by hand. If the swelling and pain is on the left or right side of the posterior vaginal union, most of them are caused by vestibular gland cysts combined with infection. In case of localized suppuration, incision and drainage are recommended.