There is rarely such uniformity of opinion on CC and every poster believes your B was fair and that you have no cause for complaint. I’m not sure why you chose to come here to ask for opinions if you are dead set on your course of action. You were not “wronged” – the fact is that the prof. followed the protocol set forth on day one and your 86 appropriately came out to be a B.
Nobody will stop you from going to an administrator to complain, but the odds of prevailing are slim and none. It is more likely that your reputation at the school could suffer (you might be viewed as a whiner, a grade grubber, someone who tries to stir up trouble when there is none etc.) and you might lose a friend (if he/she finds out you are using his/her grade to complain about your own) as a result of such action. Sometimes you just have to move on and this seems to be one of those times.
Anyway, I’m signing off on this thread.