Helping Zoe set the table for dinner, Jon wondered how it was that his mother and sister had new faces. He didn't remember wanting them to have swapped faces (he had to actually think about it to make swaps happen, but he was sure he hadn't), but it was clear that that was what had happened. Another thought occurred to him - who did they swap faces with? He didn't recognize the faces.
Stopping and looking around the kitchen, he then spotted a food product box that was used for tonight's meal. On the front of the box was a man and a teenage boy. Except, the man now had his mom's face! And the boy had Zoe's! Well, that explained that. He must have subconsciously seen the picture on the box and willed his mom and sister to swap faces with the man and boy, since his mind was on the fact that he has just swapped his face moments earlier. He wondered if the "models" who posed for the picture, wherever in the world they might be now, had the faces of his mom and sister.
He really had to concentrate better on not making swaps happen. Maybe wishing to just think about a swap to make it happen wasn't such a good idea. After all, his mind might wander again.
"Jon, snap out of it," Zoe said, getting irritated. "You're supposed to help me with the dishes and silverware."