1.I had no idea the smell was coming from an invisible "film" on my tongue.
Illustrative before & after — individual results vary.
Turns out I wasn't doing anything wrong. The smell wasn't me — it was a slick, invisible "film" sitting on my tongue, tucked into grooves a brush just skates over. Mint never touched it; it only perfumed over the top for an hour, so the smell kept crawling back up through it. The relief of finally knowing? It was never me, and it's fixable.
See What's Really There