I had the same issue on my 6s Gold 64gb, yesterday I went down to my local Apple store and met with the Apple rep, she told me she would be able to swap my phone out with a replacement device, I asked her is it the one that comes in the white box? She told me that yes it was that one, I simply told her thanks but no thanks as I was still under my 14 days to return the device, she told me that their policy was to just replace it that way, I then told her that I would think about it and left, today i reserved a new iPhone, picked it up at another Apple store and return my defective one, I simply told the guy that a family member wasn't happy with the phone because of the dead pixel, he didn't ask any further questions. What I would advise is that you try by all means to get a new phone completely sealed, as there is no excuse for them to swap it out within your 14 days, and its also worth mentioning to download "dead spotter" app as that was the only way I was able to detect I had the dead pixels, by simply looking at the phone I could not tell at all. Good luck