I leaned over the kitchen sink breathing through my mouth, and then my nose - but it wasn't any different. Every time I breathed, an overwhelming dose of peppermint filled my mouth and throat. I felt nauseous. I waited for 30 long seconds until finally I could at least breath normally. I downed some water, only to feel worse.
I just waited. My mom came into the kitchen. I told her what had happened. She reminded me to be careful with that stuff, and also informed me the store wasn't open anyway. It was 5:30 in the morning. One half hour until they open. Oh gosh.
Fortunately, I did not get sick, but it took 20 minutes until that strong taste left the back of my mouth. Even now - after almost an hour after it happened - I can still taste it a little.
Lesson learned: Don't use too much peppermint oil! And don't assume the store is open either.