I had a similar LCD fog problem, slow baked it at a low temp, around 100 F, for
a week. Then put it in a ziplok freezer bag with a bag of freshly dried silica
gel dessicant, removed it after a few days, then applied liberal amounts of RTV
silicone sealant all over seams and anywhere else I thought moisture might be
getting into the display module. Has been OK for over a year. Kind of a sloppy
fix but it worked... so far.