from the discribtion you have given you seem to have Infection-Bartholin cystitis
. the gland is normally pesent there -gets inflammed to produce the condition.
You need to have a gynac consultation for through exam. of genitals to note the cause behind.you will be given medicines according to condition found. Sometimes a miner surgery is needed to drain the abscess compleately,followed by few days dressings-to ensure healing.
It's not a major problem,but ofcourse needs proper manegment. Pl. don't worry,take care.