Not So Old Fashioned Body Swap

Jessica stood for a moment admiring the rock. It was a pretty neat looking rock after all. Just as she was about to put the rock back where she found it, John walked into the room.
"What the heck are you doing in my room?" he asked.
"Oh nothing," she said, hiding the rock behind her back. Maybe I could sell this... she thought...
"Well, than get out!" Jon said, obviously annoyed.
"Whatever, it's not like I'm stopping you from doing anything important..." Jessica stated.
"Whats that supposed to mean?" Jon asked.
"Well, my life is soo difficult. I have cheer leading practice and... and... you just wouldn't understand." Jessica threw her hair over her shoulder and smirked.
"Yeah? Sounds soooo hard"
"well, your lucky. You do abosolutely nothing! I just wish that you could live my life and see how hard it is!"
And with that, the rock glowed in Jessica's hand and she felt it get warm and threw it back onto the table. Jon could only watch and guess what would happen next.
Jon looked down at his hands. They were now thin and had pink nail polish on them. He tugged at the skirt of the night dress he was wearing. He turned to his mirror and saw a perfect reflection of his sister staring back at him and next to another girl in total shock. The stone had made him his sister's twin!
"Now this is why you don't come into my room!" Jon screamed, pulling on his long blonde hair.