dpi help

i found an app to change my dpi from 120 to whatever i want, but i accidentally changed it to 320 and now my screen items are huge and unusable on my android. i factory reset my phone and also unrooted it but the screen items are still to large. my phone says "touch the android" but it is too large for me to touch. i cannot access my phone and i need it. i tried to flash it but that did not work. please, i need help