The Two Faces of Misaki Hoshino.

Kobayakawa is an antisocial student who lives an extraordinarily ordinary life. His only talent is painting portraits, which he often does to relieve pent-up anger. One day, he meets a pretty and popular girl named Hoshino who has a secret that nobody knows except for her and her childhood friend. That is, until he stumbles upon it too by chance. Her friend had been putting make-up on her every day. Now it's his turn to keep this secret and help maintain her social life! (Source: MU)