If you have a gynecologist call her office and tell the nurse what's going on and that you are
scared and why. I'm sure they'll either reassure you on the phone or have you come in to take a look to make sure you're ok. If you don't have a gynecologist you're old enough to start seeing one and may I suggest a female doctor because of your age might be less uncomfortable.
It's hard to know from your description, but look up Bartholin's cyst and Skene's cyst to see if it's either of these. Both are quite common and have nothing to do with cancer. Good luck.
does it hurt ????it can be a boil