Jon turns into a boy with Breasts as large as Karyn's. Then they enlarge to fit his larger body. Then he shrinks until he is no heavier ( not counting the weight of the breasts) than Karen. This makes him about a head and shoulders shorter than her. Although he is still stronger and more muscular. Jon is quite handsome and everyone accepts the breasts as normal except Jon and Karen and even they forget unless someone or something remind them. To everyone this is Jon's normal shape. Jon is very popular with the girls and gets all the dates he wants despite how short he is or the fact that he is more buxom than most of the girls in the school. They don't even mind that is a genius and has skipped grades and so is three years younger than any girl in the school.
Jon is extremely happy with his new life, except he keeps thinking that he is missing someone or something.