I don't think that appealling is career suicide. It is confidential, and the worst that happens is you fail, and it'll get lost in the paperwork in the fullness of time.
What is career suicide is making a big public, legal or personal issue of it. If you appeal, keep it low key, and trust to the judgment of the system.
I'd recommend talking it through with your instructor and see how s/he feels it sits, before making any decision.