First can I ask, once you're recovered a little bit, are they going to try and find the needle? Because that would be pretty high on my priority list.
When I was sixteen(I'm 22 now) I had pretty major surgery, but almost opposite of what happened to you. It was on my jaw, because I had something called an open bite, similar to an overbite, but when I closed my mouth all the way my teeth wouldn't touch. It made eating more difficult and after they figured out what was wrong with me my aversion to meat was suddenly explained: I couldn't chew it properly.
So the surgery basically consisted of them unhinging my jaw and filing down some of the bone so that I could close my mouth all the way (they took out my wisdom teeth too, since they were in the neighborhood).
I remember before hand they gave me a relaxing type of cocktail through the IV, but it took affect really fast, and freaked me out a little. Recovery was the worst though. I couldn't speak, or move my mouth at all really, and I didn't react well to the anesthesia so I was really out of it. The worst though, was when I sat up I felt something run down my nose--blood--so I press the nurse call button, and she comes in. I can't say anything so I just hold up my bloody finger and gesture to my nose, to which she replies, "oh that's not good, let me go get the doctor." Which is very disconcerting, when the staff gets concerned. It turned out not to be serious, just a result of them fiddling around with the sinuses and nerves (which might possibly be why you're coughing up blood since it's all interconnected). Six years later and I still don't have full feeling back in parts of my gums.
What sucks the most about having surgery on around your jaw though, is it limits your ability to eat. I couldn't have solid food for about three months, and that first week I lost fifteen pounds because all I literally had was gatorade and apple juice.
And I still have some metal left in me too, though mine was on purpose--a plate and some screws, so no MRI's for me.
Sorry for the long post, but I definitely know what you're going through, and hopefully your recovery goes smoothly, though I would definitely harp on them about that needle. Your face seems a bad place to leave one.