My new screen failed the same way after replacing the display

I replaced my screen in an attempt to fix an unresponsive area which made it impossible to unlock my phone. A small black dot appeared on the bottom right of my screen before the responsiveness issue, but I ignored it as it didn't bother me. After replacing the screen, my phone worked properly for a few minutes until the new screen started to malfunction the exact same way except this time the black dot showed up after the row lost function. I tried reseating the display cable but that didn't work.