What Causes Burning And Redness In Vagina With Diabetes?

I had sexual intercourse about a week ago and after I had some burning and redness around the labia minora and majora. I was checked for a UTI and Chlamydia and they turned out negative. I am a diabetic and I get frequent yeast infections. I took a pill that my doctor prescribed and I still am having the burning sensation and redness. I made an appointment with my GYN, but I would like to know what someone else thinks.