Please go and see your doctor. It is probably just a wart or spot but you sound like you need a peace of mind on this one. I know you are only young and these things can be very embarrassing but doctors treat all sorts of embarrassing things. Ask for a female doctor or nurse. Be brave and go for it.
Have you spoken to your mum? Or is that something you can't do or feel embarrassed to do.
Are you old enough to go to the doctors by yourself? You can ask advise at the Boots shop chemist part of the shop they usually have a member of staff who is medically trained. I know it is embarrassing but lots of women have these sorts of problems.
Let me know how it goes x