The Magic Academy's Ugly Duckling

Half-blood witch Elowen has spent years cursed with an ugly face and chasing Corbin, the mage who lets his teammates mock her. When Corbin agrees to use her to distract rival star Kellan, Elowen gives Kellan her best potion and helps him crush Corbin instead.

At midnight on her eighteenth birthday, the curse breaks before them all. Corbin suddenly wants her, but Kellan had already noticed Elowen before she became beautiful, and he refuses to let her be anyone's joke again.