He'd have to think of a way out. He thought back to the original wish...and then it came to him. "I wish I could relive what happened with my wish from the time my current mom replaced my old mom until I got home that afternoon."
There was a flash, and suddenly he was somewhere else. He was sitting at a desk. He recognized the place. It was his doctor's waiting room. A careful check of the computer proved it. It was early on the morning this all started. He looked more closely at his hands. The nails were short, but carefully tended to and covered in red polish. He caught sight of himself in the reflection of the glass divider between him and the waiting room.
He was the receptionist. He didn't know her name. He looked around the desk, trying to find it. He saw a picture of the person whose body he was in with strangers, but no name. Then he found her purse. "Christine Wallace, age 25....cool, I can drive."
Wait...it wasn't cool. He'd have to live as Christine until he saw what happened. Hopefully then he'd go back to himself. Well...it was only not cool if he didn't go back. He'd travelled in time. That was cool. He got to try being a girl. That was sort of cool. And he didn't have the stone. That wasn't cool.
He picked up the phone. He could call his house and warn himself. But he found he couldn't dial the number. He hadn't wished to change history...so he couldn't. Nothing he did could change anything. He could just live and watch.