Shine a flashlight on the screen and see if you can see either the Login Screen or your Desktop. If you can then it may be the backlight that is the problem.

If not try an NVRAM reset:

How to reset NVRAM on your Mac - Apple Support

Hi

Try a reboot press the side volume button up quickly then side volume button down quickly then hold power button down until you see apple logo.

Go to books download ios 11 user guide & iPhone X guide both are free.

Cheers

Brian

Only the Plus model can you rotate the Home screen to landscape not the lock screen.

Hi

The following steps may help:

• Check that Theatre Mode / Cinema Mode is not enabled on your Apple Watch:
  • Be a considerate moviegoer with Theater Mode

• Check your Wake Screen settings:
  • On your iPhone, in the Watch app, go to: My Watch (tab) > General > Wake Screen > check that Wake Screen on Wrist Raise is enabled.
  • It may help to toggle the setting off and on again, if it is already turned on.

• Check your watch orientation settings (which tell your Apple Watch which way up and which way around you are wearing it):
  • On your iPhone, in the Watch app, go to: My Watch > General > Watch Orientation.

It works the same, however with 3D Touch, you cannot press on the icon. You just gently place your finger on the icon and hold it there until they start to wiggle and the appears. You can move it then.

Ok. So it turns out to work as follows:

     - On the Lock Screen, you swipe from the middle and up.

     - On all other screens, you swipe from top of the screen downwards.

Why the inconsistensy? It's extremely stupid, and not very Apple'ish...

I won't directly link to it, but at least in the United States this is one of those things where the policy distributed to official repair personnel is well known.  Just do a search for it on any search engine.  There are rules that Apple Stores and Apple Authorized Service Providers are supposed to follow.

Under warranty they will apparently still work on it with an aftermarket glass repair as long as nothing was damaged during the aftermarket (or self) repair process.  After the warranty, reports are that they will only perform service if the customer is willing to pay for the authorized glass repair, or if it's severe, pay for the full replacement "repair" cost which is less than full retail.

This is about it.  If anything else seems to have been replaced by anyone other than Apple or an AASP, Apple won't touch it either under warranty or out of warranty.  Under warranty you might be able to convince them to do it if you have an attorney.

Well I seem to have solved the problem. After reading about similar but less extreme cases where the internal clock was messing with things (something from iOS 10 i think).

The solution is to switch off the Automatic "Date & Time" in settings and maybe rebooting the device.

It's been perfect since I did that (24 hours ago), before that it was unusable.

What happens if you just restart the computer?

I apologize for panicking. Just now, I decided I really had nothing much to lose by just restarting my computer. So, I did it. My computer booted up as normally as before the restore, and everything is in place.

Thank you for your consideration!