Screen turns blue or distorted or staticy won't always reboot.

My iphone 5 from time to time turns to a blue screen, or sometimes the screen becomes distorted or like static; if it distorts or static the screen fades out to to like an inverted color. Its weird. I can usually reboot the phone fine right away but sometimes it wont reboot for a few hours or even a day. Sometimes it does it very very regularly, dozens of times a day, and sometimes I can go days without it happening. I'm just worried that I won't be able to reboot it at some point. Any ideas?