That doesn’t sound good or normal, Rob, unless your Christmas Singalong was several hours long with intensely loud and high playing.

I suspect you’re manipulating your lips/face muscles too much.

My interpretation / understanding of WindWorks is that more relaxed, more natural, freer the better–the 1% rule. The more efficient we play, the less we fight the horn, the better, etc.

While I’ve occasionally gotten a little sore in the corners, especally after doing flexilibity studies / harmonic slurs, what you’re describing sounds unusual.