I have gone through your question. Usually the lesion you are describing is infection of glands (Bartholin s glands) which are situated under the labia majora. They open in the inner side of the labia majora. In initial phases, there is irritation, which gradually progresses to pain and then it forms the abscess. Once the abscess is formed, it ruptures during menses and gets re-infected and grows again throughout the cycle. Initially it is acute infection and then if left untreated it becomes a chronic infection. This infection - Bartholinitis - is usually sexually transmitted infection and most of the times it is gonorrhoea. This can be completely cured by medicines. If treatment is not taken in time, it may ascend to the uterus and the tubes and may block the tubes leading to infertility. Agreed you did not have sex for 6+ months. However, how long you are suffering from these symptoms. May be initial mild symptoms could have been ignored or have gone unnoticed. Also you have to consider incubation period, comparatively symptom free period and less symptoms period also. Please visit either your Gynaecologist of STI specialist and get properly examined clinically and treated. I hope you have got the convincing answer to your query.