There’s condensation in my iMac

I never thought it’d ever happen to me, but it has. I always thought there were finger print smudges or something on my display, but today I noticed the “smudge” was pretty big and long. Then when I put up a black background, I knew immediately what it was. There’s condensation of water vapour in between my 20 inch iMac’s LCD display and the outer glossy casing. I can still do my work fine, it’s just annoying to have a tiny blur on your display. My “call in” service is over, so I have to visit an apple care centre to address this. Hope I don’t have to personally lug my 20 inch iMac to the care centre to get it sorted out. Anyone know a way to fix this myself?
DK: keep this in mind when you buy your iMac. You might wanna check with the sales rep if the issue’s been sorted out.