"And I wish that your wish yesterday didn't affect your mind," yelled Jenni.
Unfortunately, Jenni wasn't able to change much, since wishes couldn't be reversed. Sure, she was able to modify (not reverse) Karyn's initial wish that lead to this situation, but the other wishes that followed still happened anyway.
The only thing that was different, because of Jenni's wish, was that Karyn now had her original mind and personality back. She was now a tomboy teenager trapped within the body of a buxom blond porn star.
"What ..." Karyn began.
"It's okay, Karyn. I fixed everything," Jenni said. But then she looked around and saw that almost nothing had changed. "I think," she added. Even she herself hadn't changed back to being Jon.