Thanks for posting your query.
This may be due to vulvitis
and may be caused by yeast infection. Repeated scratching of that area also would have produced such swelling and inflammation. Are you a diabetic?
You just visit your consultant and get examined by her. This can be treated very easily and you can get a complete cure. Ruling out diabetes
mallitus and treating with anti fungal creams and systemic antifungal tablets will cure you.
Your Gynecologist will help in this regard. She will also rule out other possibility of STDs.
Get well soon.