It turns out Athena pocketed the coin, and becomes April's clone.

Since neither Athena nor Apollo/April had noticed that it was the coin, not Athena's device, that was the cause of the initial transformation, the psychologist attorney had thought nothing of pocketing it after the spa, thinking it was nothing more than a cool looking coin. But as she went back to her apartment with Dennis, acting like a slut, internally she still linked 'slut' and 'April May'. Both she and Dennis were more than a little sauced, so Athena only removed her pants, leaving her jacket with the coin inside on, as she rode him, neither of them aware enough to realize what was happening.

As they fucked, Athena's butt grew a little larger, a little more bubble-shaped, and as that happened she lost a few inches in height. The muscles she'd gained from training in martial arts dissipated, and her breasts expanded out until they were jiggling wildly as she moved herself up and down on Dennis's cock. Her face changed subtly, her lips becoming larger, her entire face becoming more seductive, more beautiful, and the last thing the transform was her hair, turning a bright pink and shortening, becoming more wavy. As the sensitivity of her body rose higher and higher, Athena had become a perfect copy of April May as she and Dennis came at the same time, both quickly falling asleep without realizing the change.