Not sure if this is from a yeast infection/from it.
I've had a yeast infection before, but I've never seen these symptoms...

First, I think there was a bit of itching on the labia majora. But I did shave recently, so I thought that it was because of that, and I saw no discharge, and there wasn't a change in smell.
I was sexual with someone a few days before I saw these symptoms. The person gave me oral, and rubbed themself on me a bit with their penis. That was it.

Symptoms I've had after that encounter:
My outer lips have felt really dry (bottom of the outer lips near the vagina). It felt dry and chapped to the point that when I walked, it seemed as though they rubbed together. It was hurting, and burning a lot (especially the left side).
I took a mirror and checked myself out when I went home, and it seemed as though it blistered or something (mostly the left side), and I assumed that was from it being dry and rubbing together.

I have the monistat cream, so I used it on both sides. It made it itch, but it helped.
I also went and got the monistat ovules (3 day) for a yeast infection. After that, I did see what normally looks like a yeast infection.

However, the bottom of the outer lips are still worrying me...
I kept using the cream, and the blistering has gone away. But it's discoloured (I'm black, so it looks white like dry skin), and has spread from my left labia mj., under the vaginal hole, to the right one. It also has spread to the bottom of my labia minora.

Is this just a regular yeast infection, or do I have an std/sti?