What Causes Itching And Burning In Vaginal Area?

about 3 weeks ago the top of my vigina began to itch...and when I try and look to see what is itching it burns to the touch. It is isolated just at the top of the opening of the outter lips. Also this morning I noticed what seems to be a new fold of skin just under my left outter vaginal lip?? I am going to my OB on Monday but am freaked out...any info would be helpful.