I just got done reading Sphere by Michael Crichton. In addition to being a pretty good as sci-fi read, I was pleasantly surprised to see that there is a beautification transformation!
One of the main characters, Beth, is first described as being sort of plain looking. She is in her mid 40’s, and has a sort of masculine look to her. She lifts weights so she is broad and strong looking. In short, not that conventionally attractive.
As the book progresses, and for reasons that I will not go into, Beth is gradually described as being more and more attractive to the main character Norton. At first she looks younger. Then he notices how she looks much less angular than before, and much more feminine. By the end, she is described as being absolutely gorgeous, with lush blond hair, a beautiful, young face, and a softer, feminine body.
Even her attitude and personality change for a time to that of a seductresses.
It is not a huge part of the book, so don’t get your hopes up for lengthy, descriptive passages outlining the changes. But I think it is worth a read if you haven’t done so already.