First off..I'd like to say hi, as I am a new member (just registered today)...I've finally come out of lurkdom..
Two nights ago, I decided to do an overnight treatment of tea tree oil (put some on cottonball, taped to face with a bandaid) to treat two pimples. I awoke and was shocked beyond belief. I have NEVER had a mark this dark on my face. One pimple transformed into a dark scabby circle about the size of a pencil eraser. 
Damn I feel ugly!!! LOL! The other pimple darkened a little, but not nearly as much as the one on the right side of my face (see pic below).
What do you think happened? How can I get this scab to go away? I washed my face with tea tree oil facewash (from The Body Shop) and applied vaseline and a little bit of cocoa butter. Thank God I was able to schedule a derm appt for June 10...
Oh and to top things off I'm visiting my boyfriend in 4 weeks...and I don't want him to see me like this! Is it possible to get this thing off my face in that amount of time? Thanks!!!
First of all, Welcome to the boards!
Ok - you burned your skin with the tea tree oil - it can happen when it's either undiluted, or not allowed to dry. The continuous contact caused it.
What you need to do now is treat it like a burn - wash gently twice a day, and keep it moist. I like polysporin for keeping it moist. It's an antibacterial salve like neosporin, but it seems to work better for me. Any drugstore should have it.
After you wash your face and let it air dry for a few minutes, apply some of the salve to a band-aid, just enough to cover the pad, and carefully place it over the boo-boo 
Make sure none of the sticky portion touches the burn - ouch.
I burned myself like this once with a clove of garlic - so gross - it looked much worse than yours. I had read online somewhere that rubbing garlic on pimples can kill them, so one-upped and taped a piece of garlic to my face. lol, don't ever try that one.
In the future - dilute the tea tree oil - I apply it when my face is still wet - quite wet. I use five drops for my entire face.
I use this. It's half lavender oil, half tea tree oil - soothing and antibacterial.
Good luck - it'll heal faster than you think!
i've heard of polysporin...i'll prob pick some of that up tom. is it okay to uses neosporin? i'm afraid to cover anything on my face with a bandaid now! lol! and it was undiluted...i wasn't thinking before i applied..i did it out of desperation and only worsened the condition!
Same thing happened to me last week. Worst experience ever. I know have a huge circle on my cheek. After 4 or 5 days, it did peel off and now it left a huge dark spot on my cheek. It really sucks like it is so abvious and I really dont wan't to go out. Someone help me please. How long will the darkspot stay. What do I do? I want to get rid off it immediately.