Let the battery drain dead. Recharge and retest.
Some topics covered
-Basic troubleshooting steps
-Hard reset instructions
-Manual restore instructions
-Anti-theft & recovery tips
I has a similar problem once. I was using my iPod, and I looked up, and when I looked down, the screen was white with colorful lines. I started panicking. It wouldn't turn off, and, well, it wouldn't really do anything. I let the battery drain dead, and when I plugged it back into power, it turned on and acted like nothing had ever happened. Apple devices are designed to hold up to things like that. Don't worry about it.
- Also try DFU mode after try recovery mode
- If not successful and you can't fully turn the iOS device fully off, let the battery fully drain. After charging for an least an hour try the above again.
- If still not successful that indicates a hardware problem and an appointment at the Genius Bar of an Apple store is in order.