John Matthews 
RESET [EPUB ebook] 

Sean Nelson lives an ordinary life as a security guard. Not the manliest job, but his looks make up for it — a tall, well-built man with short blonde hair and bright blue eyes. A traumatic accident causes a chemical imbalance in his brain, triggering a split personality. Sean fluctuates between pure evil and the norm, two very different life styles are revealed between mid-night and dawn. His second dark personality controls his nightmares, which intervenes with his regular lifestyle, while he learns to control the inevitable.