[Grazester]

My Nexus 4 screen started to turn yellow due to the discoloration of the adhesive between the lcd and the digitizer caused by heat. Unfortunately my phone developed a dead sport on the digitizer and no longer registers touch input there.

I just ordered a new screen. I would most likely end up giving the phone to a friend whose phone is dying

[glandium]

My Nexus 4 screen started to turn yellow too, and a few weeks later (coincidentally, at the end of last week) the battery bloated like in the OP. So be aware that you might just be covering up symptoms of an imminent death of your phone's battery.