What causes spots at the top of new screen?

I just purchased the iPhone 5 Display Assembly (LCD, Front Panel/Digitizer) to replace a shattered display. I bought the kit and highly recommend it because of the tools it includes.

Its easy to replace and the online videos are fantastic. It helps to have a decent magnifying glass and a well lit space because the screws are much smaller than I expected.

After successfully replacing the display, I notice two small light colored spots at the top corner of the screen. I suspect that it may be a faulty display but its not as bad that it warrants returning for a replacement.

What could cause the small blemish at the top of the screen? connectors? faulty display? other?

Thanks to iFixit! I saved a lot of $ by fixing this myself. It took me around 1.5 hours to complete and a lot of patience to deal with the very tiny screws.