Vaginal Sore?

So, this sounds really gross and probably way tmi, but, I have a vaginal wound where my labia and my hair meet. I don't know exactly what it is, but I know for sure its not anything transmitted sexually because those come in clusters (at least after I researched it) and I only have one. It's really painful and it 'waters'. I just need some help with someone who may or may not has had the same problem. (I had asked my mum to take me to the Doctor but she refuses)