Severus had appeared in the Shrieking Shack just a few hours ago by his reckoning. He had opened his eyes and realised he couldn't remember everything. That scared him, he had always been in control but now he wasn't. Upon awakening he had felt for the bite and found it healed, that confused him. Hadn't he just been bitten by Nagini not long before? He had meditated and worked on his occlumency and his memories had started to come back. Now he had most of them and it made no sense. He couldn't here a battle outside, he was healed and it was night when by his reckoning it had been day just before but he realised he could have fallen unconscious so that would explain the shift in time.
Eventually he stood up kind of shakily at first but he soon found his balance. Walking out he saw it was indeed night but what made him stop short was the outside. Everything looked like there had been no battle. It was all fixed.
He had to find out what had happened here. Something was obviously wrong but what was it?
Figuring the best place to find answers would be Hogsmeade he slowly started to make his way there.