I love you...nerd

Jieun is the "nerd" of the school and no one talks to her. She has big glasses and doesn't know anything about fashion. She's bullied by all the boys at her school, especially a guy called Chanyeol. One day when she helps a woman out, that women repays her with a total makeover. When she goes back to school everyone is surprised by how pretty she looks and all the people who hated her loves her...except for Chanyeol. She keeps asking herself, why is he so mean to me? I didn't do anything to him but he's still mean to me. But what she doesn't know is chanyeols secret that he didn't tell anyone. What's the secret?