Can't find this book.

[peter_j_m]

So I read this book a while ago back it 7th or 8th grade, it was about this demonic carnival that they got sucked into. The book starts with these group of teenagers at the local carnival and I remember the main character has a younger brother who had a hat that had the middle finger and the younger brother loved the hat. The only other major part of the book I remember is while in the demonic carnival the main character finds himself in this mirror maze, where if you walk into a mirror you actually walk through it and the mirror changes you and if you walk through too many you bring to turn into a hideous monster. Which that what happens to his girlfriend. That's really all I can remember besides I think the book was call Thrill Ride, but I can't find anything like it online. Hope someone can help me out!