A childhood belief about ghosts

I always thought that if you were in a room with a mirror and it was just light enough to see yourself in the mirror, but still really dark, and said 'Bloody Mary' 47 times, she would appear and come out of the mirror and break the mirror and then disappear again. And if you did that but fainted when you saw Bloody Mary, when you woke up you would have this ginormous cut on your wrist. I tried this with my firneds, however, and nothing happened.