A lump growing inside one side of the labia externa of women is painful. There are causes such as folliculitis, eczema and vestibular gland cysts, which can be treated by antibiotics, glucocorticoids or surgery. 1. Folliculitis: Folliculitis lumps are usually small, at this time you can use antibiotic medication to apply locally, so as to improve the symptoms of pain, pay attention to prevent allergies. 2. Eczema: eczema may appear small flaky bumps, itching is more obvious, the pain is mostly caused by repeated scratching, glucocorticoid drugs can be applied locally to reduce pain. 3. Vestibular cysts: due to the poor discharge of secretions in the vestibular gland, can be treated surgically, incision and drainage, to reduce pain. If a woman has a painful pimple on the inside of one side of her labia, it is recommended that she seek medical attention in a timely manner, under the guidance of a doctor, to improve the relevant examinations to clarify the cause of the disease and to treat the symptoms. Patients need to use the appropriate drugs under the guidance of the doctor, avoid unauthorized use of drugs.