How can you tell if you are using to much pressure when playing the trumpet, specifically in the upper register? Because I have been told that everyone has to use some amount of pressure, the key is to not use to much. I have heard that after your done playing and you look in the mirror if the ring on your lip is red then you used the right amount, but if it is white then you used to much. Is this true? Is their a proven method to determine if you are using to much? Thanks!