I work with college students who have accomodations and as a teacher/faculty, I would do almost anything (within my capabilities) to help a student who needs accomodations. I actually had them when I was a student, even in college.

Most of the time, the professors are used to working with students are very helpful. Many times you don't even have to show up to the class - you can set up a time/day to take the exam in the tutoring center or the instructor's office that same day.

Students don't really notice that you aren't there. Most of the time, they are so focused on doing well and studying for themselves that they probably don't even ask why you did it. You can just say, "I worked with the instructor and took the exam". Or, "I'm all set" or even, turn the question around to say "how do you think you did"?

I like Hoping's idea to see if you can get an advocate. Many student disability centers have people who can coach you through this - is this something you can look into where you are? Email is fine, too - if that makes you more comfortable. Sometimes that works better anyhow if you aren't comfortable talking to them in person.