Part of screen non-responsive

Hey guys. My Nexus 4 suddenly started acting funny today. It's as if a part of the screen is completely non-responsive. I tried restarting and factory resetting but it didn't do any good.

I downloaded SketchBook Mobile and tried filling the screen in, you can see clearly that there's a part of the screen that isn't registering touch: http://i.imgur.com/mxznb.jpg

Has anyone else had this problem? I tried searching a bit both here and on XDA but I didn't find anything. My phone is running 4.2. The thing is I think this might be a developer build, I got the phone directly through LG a couple of weeks ago and the couldn't confirm if the build was final or not.