Pretty Is by Maggie Mitchell

Everyone thought we were dead...
Two girls went missing - and now the truth is coming back to haunt them...
Lois and Carly-May were just twelve when they were abducted by a stranger and imprisoned in a cabin in the woods for two months.
That summer, under the watchful gaze of their kidnapper, they formed a bond that would never be broken.
Decades later, both women have new lives and identities. But the events of that summer are about to come back with a vengeance.
Lois and Carly-May must face the truth about their secret, shared past...
What really happened in the woods that summer?