Burn (Dragon Souls #2) by Penelope Fletcher

Something deadly lurks beneath the surface of Marina's skin, a wildness, a magickal creature born from fire and ice. After crossing dimensions to the fiery land of dragons, where not only is she a princess, but descendant from one of the most powerful dragons in existence, Marina has chosen to enter the tournamnet Aver to win the Frost Wreath. She must face four deadly quests to be crowned queen of the Ice Realm, and to win the right to hunt Koen Raad, her dragon mate. Between assassination attempts, the growing darkness in her adopted son, and the deadly quests of Aver itself, Marina's chances of survival grow dimmer by the day.