Yesterday, I went to take a picture, tapped the camera icon, and the screen went completely blank, and it has been that way ever since. It doesn't respond to any hardware buttons. The only change in the last 12 hours is that, initially, the screen was glowing slightly and the bottom hardware keys were lit; now the screen and the hardware keys are dark. When I plug it in, the charging light lights up white. Nothing else changes.
I am currently traveling on business, so I'm kind of screwed without working phone.
What can I do to fix this?