what to do, on a macbook pro 15 inch 2013 retina, the bullseye glows yellow

I presume this is a problem with the computer's backlight?

If you have light coming from the back of the computer, such as sunlight, that sort of glow can happen because of the sunlight being so bright as to get through the translucent Apple logo on the back of the screen. Covering the logo with a dark thick paper or sticky can prevent light from coming through.

If it isn't due to the translucent nature of the Apple logo, and you see it when there is backlighting in the LCD on in a dark room, then you might have a problem with the display itself. Bring the computer in for service if it is constantly reproducible.