What kind of BV treatment did you have?
Also, it occurs to me that "foul smelling" can occur after the discharge is out of you rather than inside your vagina. Have you ever tucked a clean cotton swab up inside and swished it around, and then smelled it? Sometimes a sour smell can be the result not of the original discharge (which smells pretty neutral) but of the interaction of sweat and bacteria in the area of the outer lips and top of thighs.
Usually when we go to the doctor, they swab discharge if there is a concern. Then they look under a microscope and can see if it is bacterial or candida. If you were positive for those, they'd likely give you medication particularly for the BV. Anyone can get either of those even if a virgin as sex is not required.
Do not douche, by the way.
but hygiene is also important. There are lots of little folds in that area and there can be trapped bacteria. Using plain soap and water, you can wash thoroughly the outside of the area. That may help. Sometimes using a little antibacterial soap can help too. (only on outside).
But it may be your natural odor. It may not stink to others but you are just smelling it.