Re: Mouth swab test in three days HELP!!!!!!
You may well be screwed, however....
Start sluicing with the peroxide and do -not- go above a few % peroxide unless you want similar to 3rd degree burns inside your mouth. The commercial peroxide based mouth washes, or advice from a pharmacist on the concentration would be better. I've had skin burns from 20% peroxide. What that'd do to the soft tissues in the mouth makes me shudder.
Clean your teeth 3-4 per day and ( gross ) scrub your cheeks and tongue too, then sluice again. Thing is , you need to start now. If you get any sore, white patches inside your mouth, cease the peroxide immediately.
I don't know how effective it would be as there isn't much time for fresh growth, nor do I know if the fresh growth would pass/fail the test, but at least you'd have minty-fresh breath.
The gross bit btw is scrubbing the rear of the tongue/cheeks. Always makes me gag. Yuck.
Let us know how you got on.