Does the whole screen have a yellow tint or just part of it? I could live with my discoloration if it were uniform across the screen. As it is I areas of blue and yellow discoloration, and then some that look fine.
The good news is that your display likely won't get worse. It may become very slightly dimmer over time, but that's true of all fluorescent backlights.
For those wondering, I spoke to a higher tier rep at Apple who finally agreed to send me a replacement. We'll see how it goes.
The about and 1/5 of my screen coming in from the left ... and about 1/8 coming in the the right
the center is fine ... is I just have to remember to put everything in the middle when I want to get a true colour correction