If a lump grows on the vulva and is a little painful, it is often caused by the following reasons. The first one is caused by a localized boil on the vulva. This lump will protrude from the surface of the vulva skin and there will be localized redness and swelling, and in severe cases, pus may also appear. It is advisable to wash the vulva and apply topical Bactrim or Erythromycin ointment for treatment. The second one is caused by vestibular gland cysts combined with infection. In this case, the mass is under the skin and is painful when touched by hand, often because the vestibular gland ducts are blocked causing the vestibular gland cysts to become infected and therefore cause local pain. Anti-inflammatory treatment can be given clinically, preferably with broad-spectrum antibiotics combined with metronidazole for anaerobic bacteria, administered intravenously. Otherwise, there is a clinical risk of localized septicemia, which can only be treated by incision and drainage.