dead pixel?

You can go through Nokia. Your device has a 1 yr manufacturer's warranty against hardware defects.

Contact Nokia Care and see if they cab send you a replacement device. They should include a box and shipping label so you can send your phone back to them
 
My first red Lumia 920 had 4 dead pixels! I just got it exchanged in my local P4U store.
 
Yeah can see it alright, doesn't matter what it is though really, be it a dead/stuck pixel or dust under the screen. It's not right and you should be able to get it exchanged.
 
I was watching a movie on my 920 the other day - cranked up the brightness, and voila, a stuck pixel! Super tiny, but annoying nonetheless, and almost right in the center of the screen. I emailed Nokia Care and they said check with the place I bought it (ATT store) and if they won't replace it, send it in. I'm a little reluctant as everything else is working great; I don't want a creaky replacement with a dusty front camera and poor battery performance freezing up on me :) LOL