Accidentally turned brightness to black on iphone

Ask Siri to increase screen brightness.

Lowering Brightness using the Control Center will not make the screen so dark that you can see nothing. There is something amiss in your post

In extremely bright light, the pupils constrict and the screen becomes black to the human eye.

You’re welcome and certainly not an idiot. But in a moment of panic it’s easy to overlook some basics. I hope you have a great day!