I play with an upstream embouchure (i believe type 4a?) and I also play in the red of my upper lip. When I play for about 30 minutes or longer, i feel (with my tongue) slight abrasions or cuts, abrasions being a more accurate word. What causes this and what can I do to change this? I just want some thoughts because hopefully soon I will be getting a private teacher. Although he's not a professor or anything he seems knowledgeable enough to help me with my problems and to also help me progress as a trumpet player. Im new to all this so any and all information would be helpful and very much appreciated.