How To Treat Jagged Skin Around Vagina?

Whislt doing a self exam of my vulva using a mirror, I have noticed that when I open myself slighlty, I can see the opening to my urethra and my vagina. The problem is with the skin aroundthe vaginal opening - it seems to have a jagged edge. Is this normal, or a sign of something? I have sex 2 a week on average, it isn't overly rough, I have had cervical smears and STD tests in the past and they have been fine. The method of contraception I use is a Mirena Coil that was inserted in June. It was right after that that I first noticed this, however, I hadn't checked there before, so I don't know if I've always been like this. I am 26.