iphone 6 screen little dim on top of screen
screen is little dim then rest of screen in white background. is it uneven backlight or something else and is software bug or hardware problem
iPhone 6, iOS 9.2.1
To make sure it is not software related, force restart the phone by holding the sleep and home button for about 10sec, until the Apple logo comes back again. You will not lose data by doing that, but it can cure some glitches.
If this does not help, set it back to factory settings and check the screen again. If still no luck, get it checked by visiting an Apple Store or Apple Authorized Service Provider next to your place.