Suggest Remedy For Blisters On Vagina With Irritated Skin Around It

I've got a blister on the outside of my vagina on the hymen, and also one at the side, but that's more rough.

There also feels like there is a little on just inside the vagina.

I am a virgin, so it can't be an STD can it?

I'm really worried, i've been to the doctor, and she's given me 3 different creams but its no use, they're not working.

The skin just outside the vagina is really irritated, but my doctor doesn't think it's an infection.

HELP?!