Ok, so I'm a High School Trumpet Player (extremely cliche by now, I know), and I've recently found out my problem with playing high notes... It was linked to my corners, because I was pulling them down and back, which stretched my upper lip and resulted in a lack of range and loss of endurance ( I could only play to a high A-C consistently, and my High D's were rare ). I now simply say Mmm (Not sure if I should roll my lips or not) and pull my corners towards my GUMS.... And I honestly think that's a common misconception for a lot of trumpet players because they hear tighten your corners and immediately there are multiple variations to tightening them, and by tightening them in the wrong direction or way you can hurt yourself... (But then again, this works for me, not for everyone obviously). But anyways, back to my point. I recently made this change and I can play to a strong E/F with a weak (in terms of volume) high G (as in however many ledger lines above the staff that is, six I think.) HOWEVER, after doing this Tuesday morning (I just learned how to fix my corners Friday and I was taking it slow, working on range building exercises and long tones to get used to my new corner setup; however I diverted from this take it slow method horribly on Tuesday) my lips were EXTREMELY stiff by fifth period (Jazz Band) and I lost my ability to even play a high C. I'm 99% positive I'm not using any pressure at all really, because the first thing I noticed that morning was how painfully easy it was when you do it RIGHT... I think the reason my lips are so stiff is because I have never played a high G before in my life, and I was doing ALOT of arpeggios... Up an octave. I got that sort of adrenaline rush where you start playing high notes and you don't want to stop. I carried on for about 30 minutes, and lo and behold, wednesday evening, my lips are STILL feeling like cardboard. I did not warm down (major mistake I presume) after that little session, either. Is there anyway I can help my lips.... "un"stiffed? Any help is much appreciated, thanks! PS: I have big lips in my opinion, if that detail is of any use. I also can't play pedal tones; I can play a good, fat F#, but I can't play any lower. My director is going to help me tomorrow with learning it, because I don't really understand the way my private lessons teacher explains it.