It looks like a Bartholin’s cyst which is quite common. If it does not hurt, it means that it is not inflamed. I would seek a doctor if it grows larger and starts to hurt, otherwise it can go away without treatment.
w/o treatment it will go away in about a week. sit in a Epson salt warm bath and it will alleviate it until you can see your pcp/gp. wear lose fitting underwear to let it breathe and not cause pressure…good luck