Hello, I would be happy to help you with your questions.
It sounds like you have two things going on:
1. A vaginal yeast infection
2. An inclusion cyst
- a painful sore lump at the vaginal opening representing a blocked sweat gland
This is often treated with warm soaks to aid in its draining. If it does not improve, this needs to be seen by a doctor and assessed for draining.
I hope that this helps and good luck!