I Have Two "blisters" On My Vaginal Lips, They Are

I have two "blisters" on my vaginal lips, they are red and swollen and then on the opposite side near the top, it has split open. I have not had sex or anything going on for a long, long time, so it is nothing that has happened that way. It started out as like a sore spot that felt like a pimple maybe starting and now it is like two blisters, round, red, almost looks like a burn... I thought I had a yeast infection and I used the 3 day treatment and the cream, which I finished, because I was itching so bad, that is better, but now I have these areas and they do not seem to be healing up