I jail broke my iPod touch 4g and I let it die. It won't turn on. What do I do?

The iPod is updated to the 4.2.1 software and the jailbreak is tethered. So I let it die on accident and now it won't turn on. I tried to go into iTunes to restore it but iTunes won't even recognize it. I've even tried updating iTunes but it still won't recognize anything once my iPod is plugged into the USB cable. I don't know what to do anymore, I just want to restore my iPod back to normal I've learned my lesson about jail breaking! Please help. Please.