The Buried and the Bound by Rochelle Hassan

A contemporary fantasy YA debut from Rochelle Hassan about monsters, magic, and wicked fae, perfect for fans of The Darkest Part of the Forest and The Hazel Wood.
As the only hedgewitch in Blackthorn, Massachusetts—an uncommonly magical place—Aziza El-Amin has bargained with wood nymphs, rescued palm-sized fairies from house cats, banished flesh-eating shadows from the local park. But when a dark entity awakens in the forest outside of town, eroding the invisible boundary between the human world and fairyland, run-of-the-mill fae mischief turns into outright aggression, and the danger—to herself and others—becomes too great for her to handle alone.
Leo Merritt is no stranger to magical catastrophes. On his sixteenth birthday, a dormant curse kicked in and ripped away all his memories of his true love. A miserable year has passed since then. He's road-tripped up and down the East Coast looking for a way to get his memories...