Your plants will be fine. They may look like they are not growing for a week or so, while they recover from the sun burn, but they should take off nicely. I must disagree with partcleguy in that since you have heat problems, you definately don't want the fan blowing down on the plants. This will move more hot air down to the plants instead of away from them. If you have a fan at the bottom as I suggested, and have it blowing up onto your light, this will not only cool the light, but it will move hot air up and away from the plants and also keep the air from stagnating. It can even be a fairly small fan, so the precious middle area where light is the most intense can still be mostly taken up with weed. You just need a small hole in the center of your grow for the air to flow up to the light, maybe 3" diameter.