Burned my cheek with tea tree oil a couple months ago, after 15 nights of rubbing it undiluted into the corner of my mouth to get rid of some deeply infected ingrown hairs. (looks like a red cyst). The burn made my mouth look like Heath Ledgers Joker because it went from the corner of my mouth to bottom left cheek.

This is what you do:
-STOP USING 100% TEA TREE OIL.
-STOP USING TEA TREE OIL UNTIL IT HEALS (This may seem like an obvious one but seriously, don't let tea tree oil near that part of your skin)
-I applied Polysporin; not neosporin
-My huge burn went away in a month or less which was pretty surprising. People kept telling me I had ketchup smudged on my face.
- Don't worry about it, it will heal faster than you think.
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I burned my nose with tea tree oil last night