Kind of violent dream. Please help?

Okay.. I had this really violent dream, I'll try not to be too graphic with the the details, I'm just wondering what this means.. Okay, the dream: I was in a room with my female friend, but I wasn't aware the she was there at the beginning of the dream. A few moments later, three males enter the room. The male in the middle of the trio is someone I have been enemies with since my childhood. He sees me, and then proceeds to have the other two males hold me down on the ground. He then sees my female friend, and pively staring at her, and then tells her to leave the room. She does as he says, without looking back as she gently closes the door behind her. He then begins to move towards my body as I struggle to get out of the grasp of the other males. He looks into my eyes, and just stares for a short while. He pulls a small object out of his pant pocket, which turns out to be a small, sharp silver knife. He looks back at me, and begins to move the object near my face. The blade enters my nostril, and he begins to twist the knife slowly... Thats all.. i woke up.. Can someone please tell me what all of this means?