Welcome to Android Central! Does it ever move? Is it there even on a black screen? When you reboot, does the dot immediately show up when the screen come on?
And does it show up as soon as the screen is on, or does it wait until the bootscreen animation is complete and the lockscreen is showing?
Must be a hardware defect, due to the drop. If it remains stable, I'd just live with it. If it starts spreading, you'll probably have to replace the screen.
Posted via Android Central App.
Please excuse any typos or autocorrect derps.