I’m so sorry this happened to you. I’ve had plenty of “why me” moments and shed many tears over this as well. But you absolutely have to email this professor and be honest about your situation. I understand it’s the last thing any of us want to do but you need to also be honest with yourself about your current limitations. You are obviously talented and competent at what you do, you don’t have to let your stutter taint that. Please, promise me you will do this…