I think what CBS should do is let the next few weeks happen on their own, and not tell the other HGs that Annie was the Saboteur. Then, once three or four Houseguests have been evicted, tell the HGs that one of the evicted HGs is coming back, but instead of doing an America's Choice thing, just let Annie back in. She can't win the $50,000 anymore, but she'll get another crack at messing with everyone. And until then, still show Saboteur videos to all the HGs to keep tension high.