Warriors of Wind and Ash by Rebecca F. Kenney

The dragon prince would burn the world for her. But first, he must do something more difficult… pretend to be human.
Following the dramatic events at the end of “Serpents of Sky and Flame,” Kyreagan makes a difficult decision, and Serylla struggles to survive in her new environment. As magical complications arise and new enemies are revealed, Kyreagan must learn how to act human in a setting that is completely new for him, all for the sake of reclaiming the treasure he lost. Meanwhile, the dragons of Ouroskelle face an unexpected threat to themselves and the next generation.