How To Get Rid Of Itchy Vagina?

Hi doc...I have severe chaffing and itching and my vagin is wrinkly I have been treated for bacteria vaginosis and for any STD's, hoever im negative for chlmydia and gnnrhea....i dnt understand the irritation....i also heard of putting ypgurt to relieve......what could be wrong and how can I fix it?.......if the yogurt recommendable how should it be apllied? and for hoe long?