How do I get rid of the blur on my iPhone lock screen?

Try and force restart the iPhone to see if the issues persist

For the iPhone 6 the instructions for that are

Force restart iPhone 6 and 6 Plus, iPhone 6s and 6s Plus, iPhone SE, or iPhone 5s

1. Press and hold both the Sleep/Wake button and the Home button.
2. When the Apple logo appears, release both buttons.

If you have a newer iPhone:

1. Press and release the volume up button.
2. Press and release the volume down button.
3. Press and hold the side button.
4. When the Apple logo appears, release the button.