Mondays Are Red by Nicola Morgan (Kindle edition)
I got this sent for free when I bought some of Nicola's other books as Christmas presents for my sons. Read it on my journey to and from London last week - it was the perfect length.
Teeange Luke comes round from a coma and finds he has synaesthesia - his senses are muddled so that he hears colours and smells sounds, etc. There's a demon lurking in his brain which makes him do bad things; there's also a beautiful girl with cinnamon skin and 'hair as long as the sound of honey' who may or may not be a figment of Luke's imagination. He wants nothing more than to regain his strength, particularly in his bad leg, so he can run in school sports day. The demon has other ideas. Luke's sister is in trouble - stalked in Luke's head by a sinister man in a metal mask, then captured for real by a perverted man who stalks the nearby woods. Luke has to battle both real and imagined foes to save her.
This book has been taught in schools and I can see why. It's a wonderful example of what can be done with language - words stay simple while phrase and simile soar with beauty. Writing from the POV of a character with synaesthesia gives the author unlimited scope for describing things in wholly new ways, and Nicola has done just that. The imagery melts on your tongue like the colour of birdsong.
(I only once experienced the joy of muddled senses, whilst, ahem, 'under the influence' many years ago. I listened to Duran Duran's Save A Prayer, and saw that the song was a rich velvety chocolate brown.)