What Causes White Spots On Vaginal Lips?

I have notice a couple of white spots on the right vigina lip, or maybe I should say right at the opening area on the edge. I did go to the doctor a while back, and she said I had a bad yeast infection, because of all the white stuff that was visiable, but I have taken med for a while been off for 6, or 7 months now. this does look some what different because it is more distict,