Went in a couple months ago to replace my iPhone 6s Plus screen. I was charged about $100. So I got that fixed. My the time I went home I realized that front camera wasn't working. So I went back to the place with my receipt and turned out the guy "forgot" to plug in my camera. So he fixed that issue. A couple months later I realized that when he replaced the screen, I noticed these white dots on the screen from the light. At this point i couldn't do anything to fix that issue.
I recommend just going to Apple and having them professionally replace the screen for the same price and well done the first time.