Acer Iconia tablet’s erratic touch movements

My Acer Iconia A1 tablet started to have touch issues. Even without touching the screen, as long as a certain part of the back cover is touched, the screen moves on its own. This started after the tablet was accidentally dropped. There was no visible damage on the tablet, no bent plastics, cracks and scratches, but it's acting really weird lately. My question is, will this be covered by the warranty? Is this a hardware problem or can this be fixed by resetting the device which means losing all the apps on it?