i had a similar problem, my hikvision turret cameras were down for 4 months before i could power them back up, and within a few days of powering them up, they developed moisture in the lens and ir led after the first foggy morning. I disconnected power, took them down, pulled off the micro sd slot cover, let them sit for a couple of days, all the while reading about swapping out desiccant bags or taking them out to cook them so as to remove moisture, but i didnt want to tear my cameras apart, so i powered them back up with the sd card cover still removed, and left them in a closet with the nvr running for a couple of weeks (probably longer than needed, but i had the time). when i got to the point of mounting the cameras again, i took some automotive silicone grease to the rubber gasket on the sd card slot caps, reassembled, and re mounted them. been running great for over a month now, through heavy FL rains and drastic temperature changes with no lens condensation.