Tears can happen, Ive had small tears happen at the back of my vagina, most common if I havent had sex in awhile, more rough sex, or just too frequently in a short period of time it gets irritated etc. I just made sure the area was clean, let air get to it as much as I could and just let it heal on its own if its such a small tear. If you're concerned and its a larger tear, you can go to the doctors and have it checked out, but most often they'll heal on their own.