Yesterday I noticed, I have a small canker like sore on the inner part of my vagina. It hasn t caused me pain yet, but when I m sitting I can feel it especially when I shift my weight. It feels like it could get sore from irritation soon. I m concerned because I ve never had this happen to me before. I ve had a canker sore in my mouth for about 2 days, but the sore in my vagina isn t a whitish gray, its just red.