Dead pixels/Refurbished phone (Blackberry Tour)

Hello, I just got this refurbished Blackberry Tour about 2 months ago and have had no problems, until now. The other day I turned on my phone and noticed little black squiggly lines, almost looked like someone scribbled on the screen with a black pen. It wasn't big or anything but as of recently it got bigger and I thought it was a scratch, but it's not on the outside of the screen. It's been bothering me because I can't see some things. It appears to be dead pixels, but my question is, since my phone is refurbished I was wondering if they would still replace it? or do I have to pay for a whole new phone? I still have warranty since I bought it in October but my dilemma is that I don't want to have to purchase a whole new phone over it.

Help?
Thanks!