I tried to click the "thumbs down" on one of those standard autobot answerers that try to link the asker to illegal cheat sites. But instead I clicked the "thumbs down" on the answer above it (which was actually a pretty good answer). Is there a way to reverse your rating?
Not at present although let me tell you a Yahoo Answers secret.
It takes two seconds roughly for a thumb ratting to fully save on the Yahoo Answers forum. Should you make a mistake quickly press the back page function on your Internet browser , then return to the question.
If you pressed the button fast enough the rating would not have saved.
No, thumbs up and down are forever. If you feel remorse and can see that person's profile, go give them a "thumbs up" on some answer where they've already won "best answer" and that earns them a bonus point even after "best answer" was chosen.