I need suggestions! I think there are several factors or possible factors to this..

-I was just gone for 10 days, and didn't play the flute at all (i wanted to take it with me.. but didn't cause I knew I wouldn't play on vacation) and I probably didn't play for another 4 days BUT I did play my piccolo a little bit those days (We starting marching band camp the day after I got back but we have only played a little pit)

-I have a cut on my lip kind of.. it basically looks/feels like its a cold sore only its from a frisbee haha.. It barely hit my lip but it did make it bleed a little bit. Its on my bottom lip. Would that maybe disrupt the airflow into the flute? When I try to play higher notes (like C4 and up mostly) it feels REALLY weird like my air is kind of getting stopped partway or something. Its not a very steady flow. Or maybe its just harder to direct where my air is going or something. I also kind of feel like the air is going through my teeth sometimes which is also weird but I've had that before, mostly with picc (i know i need to relax more on picc and I'm working on that.. but i usually don't have this problem on flute!)

-and possibly just the fact I've started playing my picc again for marching? Last year I hardly played my piccolo at all after MB ended (although this year I want to play it more during the year) so maybe its just getting used to play both instruments again? I don't really remember any tone issues last year, although this was the time I was looking for a flute.

I've worked SO hard this year/summer in the upper registers and I REALLY need to get working on getting my 3 octave D scale ready for All-State (thats my goal) but I can't work on it if I can't even get notes before that out!

Any help would be appreciated! I really need my tone/upper registers back..

just try practicing, get in a routine where you pratice both daily, and it will come back.