The dot or dots may be caused by a software/app you've recently downloaded and installed. To check if this is the reason, start your device in Safe Mode, where only the pre-installed software/apps will run. If there aren't any dots on the screen in Safe Mode, then the dots are caused by a software/app you've downloaded. You need to find out which one is responsible for it and uninstall it.
Check out the don't know how to boot in safe mode guide if you are not sure how to boot into Safe Mode.
If you don’t receive the email in the next 2 minutes please check your junk folder, and add [email protected] to your safe sender list.