If a bag grows on the vulva and is very painful, the following two causes are common: 1. Boils formed by acute inflammation of the vulva, which will be red, swollen, hot and painful locally. It is recommended to keep the vulva clean, take oral antibiotics, and apply Bactroban or erythromycin ointment locally for treatment. Do not eat sour, spicy, stimulating food during the treatment, after about 5 days the symptoms will be significantly improved. 2, in the vestibular gland due to glandular obstruction and the formation of cysts, and combined with local infection, the internal pressure increases will lead to localized more serious pain. In severe cases, abscess may be formed, and incision is needed for drainage. It is recommended to keep the vulva clean in daily life so as to avoid inflammation.