You noticed something blue on the pool deck next to Lydia. Looking closer, you realized it was a small puddle of water liquid a slightly lighter shade of blue than Lydia's spandex skin. The puddle seemed to be slowly expanding. You then realize Lydia's spanex skin looks a little odd, like it too has grown a lighter shade.
You alert Lydia to this. She opens her eyes and sits up, examing her hands. Sure enough her hands are starting to look fleshy again. You notice where she had been laying on the pool deck is a body-sized puddle of the liquid. It quickly becomes apparent that the spandex skin is turning liquid and melting off Lydia's body.
Lydia says it feels strange and she deciedes to dive into the pool to wash it the rest of the way off. You watch as she plunges in and swims a lap underwater. Her body seems to be taking on a flesh tone all over but it looks no less mer than before.
Her lap finished, Lydia pulls herself out on the pool deck next to and you both look over her body. All the blue spandex and accompanying yellow stripes are gone, replaced by Lydia's normal skin. Her swimsuit is completely gone and you enjoy the view of her nakedness, now free of spandex.
But while the spandex is gone, nothing else seems to have changed: Lydia's breasts are still enlarged and below her waist is a mermaid tail, although the same skin as the rest of her body with no scales. Everywhere the spandex had been - her entire body below her neck - was also completely hairless.
"I thought I was supposed to change back to a human now?" Lydia asks, confused.