Sounds like a bad Display. However, to be sure you can we can toggle the Display setting in case the display is stuck in some weird mode. Open the Display System Preferences/Settings and change the display resolution. Apple has changed how the display resolution is shown in the Display System Preferences/Settings. With more recent versions of macOS the "resolution" option is now shown as "Larger Text" or "More Space" (the latter means "smaller text"). Just choose any of them, let the display adjust, then toggle it back to the "Default". If this works to fix the issue, then it may just be a one time issue.
If this doesn't help, then you can try connecting an external display and enable mirroring. If the external display is fine, then it means the laptop's built-in display is bad and the laptop will need to be repaired.