Screen not responding to touch

Hi, the easy fix would be to perform a hard reset. Hold the home button and power button for up to 30 seconds or until the devices turns off and back on again. If the touch starts working again, then great! If not, you will need to perform a digitizer repair. Remove your current glass and install and new screen. This will then fix your issue. iFixit has lots of guides on how to repair the glass digitizer.