If you have a fresh cut, go see the doctor. I don't see any reason to discuss it with your mom, just tell her you want to see the doctor because of something more innocuous (like you want to rule out a yeast infection or a uti). A doctor can't do much if you present with a healed cut, but he will probably be able to tell you where the cuts are coming from if you show up with one. Are you having unprotected sex? and if so, does your partner have genital warts or something else rough about his skin, or does he do something rough with his fingernails every time? (And if you are having unprotected sex, is it because of thinking PCOS will provide protection against pregnancy? If so, please think again and use protection until you can get an IUD or on the Pill.)