Not disappear, but depleted. He didn't tap into his Bijuu chakra, so no way he should still be up and running after him opening up all 5 gates. The hits that he had given Gaara specifically limited his chakra flow to the point where he should've been done and out.
He wasn't fully exposed because he was the main Chunin Exam antagonist and since he was Shikaku's host, it would have made sense for him to fight with Naruto and learn from him.