How to fix iPhone screen going white and crashing?

Okay so I’m up to date with IOS updates, and at first my phone started having these dead spots which wouldn’t respond to touch, and then now suddenly the whole frigging screen goes bright white like a flashlight, I can see the icons at the top flickering slightly, and then the whole thing goes black? What can be the cause of this, and how can I fix it?

[Re-Titled By Moderator]