Mikey's Gone?

After Jen was done peeing, she left the bathroom, expecting to see her now *older* brother standing there laughing at her. But he was nowhere to be found. At first thought, Jen saw this as a good thing, but then she thought about the fact that if she's not around to hear any wishes, she'll think that the new reality *created* by the wishes is normal. Maybe Mikey will wish that she'd think that she really *is* a girl. Jen didn't want *that*. She wanted to be Jon again. So, she ran around the whole house, looking for her brother. But he wasn't there. Where did he go?