The worst is exchanging out a device for one that has more dead pixels or a bigger issue. Happened to me with the original iPhone. I had 8 of them. Yeah, I said 8. Luckily for me the 3G was perfect on day one. I got so fed up with going into the store that I started calling and complaining. Apple then upgraded me to a 16 gig for free and got that only to have a blazing red stuck pixel right in the middle of the screen.... had them send another and that was actually fine. It's now unlocked and on the Tmobile network in my girlfriends hands. And if it can take that punishment - it's rock solid. (She could care less about taking care of a phone - not her thing)
I would return it. I returned mine after a week for the light leak issue -
The one they gave me has the same issue, just haven't had a chance to go and get another one. So that would be my third. If it happens again I am going to call and complain but I already have the 16GB one. Maybe they will give me a white one -