Oh no can you try a soft reset by holding volume down + lock button at the same time until your phone vibrates and reboot itself. Was your lumia 920 running windows phone 8.0 or windows phone 8.1Developer Preview ? If this does not resolve I will suggest you to let your lumia 920 run out of juice and then connect it to a charger and perform a soft reset :smile:
This happened to me on my 1020 when I was about to take an AP test, bad timing I say and took it like 30 minutes to shut off. It's a rare occurrence but still needs to be addressed.