Oh I feel for you. I had a similar problem with my youngest in the 3rd grade. The teacher managed to take all his self esteem away with consistent ridiculing in the class room because he was a slow reader. It took me a couple of years after that to get his confidence back. I found out years later that she was eventually fired and that she literally hated "male" students.
I don't know how to advise you - except to suggest you examine your side of the story and if you truly believe that you are right, don't give up the battle. With all due respect to so many wonderful, dedicated teachers out there, that one bad one can have a devistating effect on a child. Keep in mind that you also have a "creative" kid - they tend to be super sensitive.