Want Me, Take Me, Haunt Me, Make Me by Isabel Crowley

Hazel Lewis has a serious problem. The guy who hired her to conduct a seance before he died turned out to be a serial killer with a demonic contract, and the seance itself was a trap. Hazel escaped with her life, but not as she knew it: the bite of a demon is spreading through her body, letting the supernatural bleed into the world around her, and the now-dead serial killer is waiting to take over her body if she dies. 

Hoping to contain the damage, Hazel moves to a small house in a remote location. She figures she'll stay on her own until she gets a handle on her new dark reality, but she soon finds out that she's not alone. There's the reporter demanding answers, the friendly neighbor with chemistry she doesn't need and problems he can't talk about…and the mysterious face she sees beyond her window, watching her every night with glowing red eyes.

Making her hunger.

Hazel knew a little bit about the world beyond the physical. Now she's learning how much she doesn't know, including who she can trust...and who she can become if she trusts herself enough to give in to the shadows stalking her dreams.