Well, from what I've read it's impossible not to dream, apparently I just forget my dreams,I just see nothing, just darkness. Well the thing is, that happens almost every night, and the nights that it doesn't happen are even worse[Usually once or twice a month], always nightmares. To make it even scarier for me, when something bad happens to me in a nightmare I usually wake up with something resembling what happed in the nightmare. Just to help you understand better, One time i dreamed that i was in a frozen wasteland, a few seconds after looking around, a pack of wolves spotted me and ran after me, one of them lunged at me and cut my hand, I woke up feeling really cold, with cut marks on my hand, or another time, when I dreamed that I was dying, all I felt was pain all over my body, I was sleeping with an air conditioner on, yet I was sweeting like crazy.I'm sure some of you must think I'm making this up, but i'm not so please don't post saying things like "This is fake".

If you were moving around in bed in your dream, and then cut your hand on the frame of the bed, then it would affect your dream. Sometimes I hear noises while I'm dreaming, and they become a part of the dream. For example the fire alarm was some kind of beeping that meant something else in my dream. I would assume the same thing happened with your dream, you were cold and you cut your hand and your dream changed to reflect your senses.
Also It is really common to sweat when you dream. Sometimes I wake up and am really sweaty whether I dream or not.
I've never heard of dreaming just blackness before. That is odd.
Look up lucid dreaming. You can learn to recognize when you are dreaming, and even control them.
I have been practicing, and can now realize that I am in the dream, but if I think about it too much I immediately wake up. I have only been able to control a dream once.
i sincerely hope that its nothing bad and whatever it is will stop. maybe before going to sleep just say a little something like "please leave me alone. i dont want to be hurt and i dont want to hurt you. i love you" but be really polite and tell whatever it is to leave you alone. again, i am being totally serious. good luck!! :)
I think the best dreams I have are when I'm relaxed and focus on things that make me happy. Perhaps your imagination is a bit too active? I know mine is. I can't even watch "Locked Up" before going to bed...It gives me horrible dreams like people chasing after me and convicts trying to kill my family.