Actually, I'm quite sure it's a Bills logo, which I've seen other players wearing. The only thing is that it looks like he's wearing it on his bottom teeth, so the logo is upside down.
The pic in this link shows the logo clearly. http://www.buffalorumblings.com/bills-news-notes/2015/9/29/9414181/tyrod-taylor-off-to-hottest-bills-qb-start-since-2011