Bijin Kakumei

From Chibi Manga: During sixth grade Yuki made a love confession to Jun, an extremely beautiful boy. She was extremely shocked when he started teasing her and called her fat and ugly!! Three years later, Yuki has become beautiful by putting in great effort everyday because she wanted to get back at Shin. She transformed into a very beautiful girl! She was accepted into the same high school as him to plot her revenge, but her childhood friend Migiwa who knows everything about Yuki's past is attending the same high school!?