You never know until you ask. Seriously, the worst they’re going to say is no. Most teachers want the best for their students, and putting a student through something like this is not the best thing for them. An experienced teacher knows how to ask the right questions to gauge whether you are prepared but having an issue or whether you’re simply trying to buy more time. I would ask. ETA: If you do decide to tell your teacher, I would include a short counter to the “this will prepare you,” etc. that they will likely say. It doesn’t have to be drawn out, just something like, “I would normally totally agree that things like this are valuable to use later on, but this is not a normal situation. I’m not sure why, but my condition is particularly bad right now, and it goes beyond nerves or embarrassment. My condition is flaring up right now, and the only thing that will help it is time.” Maybe something along those lines.