I'm trying to track down a YA novel I read some time around the mid-late 2010s. It was relatively recently published at the time, so I don't think older than 2005. It had a really short, snappy, kinda forgettable title
It was a psychological thriller kinda deal. The main character was a late middle-high school boy who's a rule-following good boy. But then for some reason his reflection starts changing to be more of a bad boy every time he looks at it. Like it starts getting piercings and dyeing its hair and the changes start to show up on him in the real world too. It also talked to him about how he was making him better. Or maybe it was the other way around and he starts as a punk and gets prep-ified? It's one or the other for sure.
I remember he saw it in a car mirror and the reflection in the school trophy case. He gets paranoid and tries to take measures to hide from reflective surfaces. At some point he gets swapped with his reflection, and he gets stuck in the mirror world and only exists in reflections. I know the mirror dimension wasn't like a developed world either.
That's all I can remember. Any help is greatly appreciated!