Hi Oliver,
Depending on how heavily you doused the port with the contact cleaner, it's possible some of it made its way inside and got onto the LED/backlight/polarizer assembly. We've seen cases where a similar thing happened with isopropyl alcohol, and luckily after a couple of days the alcohol finally evaporated and left the screen okay.
In your case I'd suggest giving it some time to allow for the cleaner to dissipate; it may fix itself all on its own. If it still looks like that in a week then it might be worth considering a screen replacement.
Let us know what happens; if it doesn't clear up on its own, add some pictures to your question of what you're seeing and we'll see what we can do for you then.