Before We Burn von Elaine Hoekstra

Nettie has trained her whole life to become the next Healer of her coven in order to cure the magic-draining illness that plagues her village and killed her grandmother. The only problem is, she must apprentice under Namira, the very Healer who failed her grandmother. But when the Council comes in search of help to fight the rapid spread of the illness, Nettie must choose to set old grievances aside and work together with Namira or face the destruction of her coven and the fate of magic everywhere.