My Ipod touch 4G screen flickers white light

My iTouch 4G is rapidly flashing white light throuch the touch screen. I noticed it after charging it, but then it went away for awhile. A few hours later it came back, and much worse. It was working perfectly fine yesterday. I already Restored it, but it hasn't stopped. It had screen damage (twice) a few weeks ago but it was repaired. I will be taking it back to where it was repaired on Monday, but i want to know what is wrong with it / why / can i fix it myself.