Hi!
There are a couple of potential problems that could cause similar symptoms.
Yeast is probably the most common.
If you were my patient, I would probably do a biopsy though, as your symptoms sound somewhat suspicious for lichen sclerosis, or eczema. These conditions usually respond well to topical steriod creams.
Sometimes the dark pigmentation can be a sign of elevated insulin levels, so I would probably also check for diabetes with a fasting blood sugar.
Finally, if you are old enough to be close to menopause, hormone therapy might help.
Good luck!
Dr B
Well I'm sorry you are having this problem, I too had this and it took awhile (well about a week) to go away n came back again after about a week. I have no idea what it is or how to fix it, I kinda hope I could know what helps or why I get it sometimes. Sorry I am of no real medical help just know i know exactly what you are talking about and it is so tender and just not fun. wish you the best of luck to feeling better!