Pale Leopard gecko

Question
My son's geckgo (adult) was sunbathing on his rack yesterday evening and I touch it just to make sure  he was just sleeping. He was just sleeping thank goodness but did not seem his normal self. This morning he is all pale in color except around his mouth area. Again on his rock which seem to be more than normal. My son thought he was getting too much light and turned it off. We use a night night and a day light. Temp in cage seems to be ok other than humidy did change some (We've had windows in house open). Has been eating ok, other than still has two cricket from feeding him on Monday (we feed crickets every other day with calcium and crickets ae gut feed). Do you think he is shedding or could he be sick? Or should I leave work to have seen by vet? I'm also concern that Son turned light of and we do not have a heater at bottom of cage. We are not suing sand and use the (not sure what it's called when geckos are babies due to easy to clean and know that it will not eat sand).

Answer
Well, definitely don't turn off his light.  Reptiles bask in the sun when they want to warm up.  I will ask how you are checking the cage temperatures--do you have a thermometer with a remote probe, or one of the stick-on kinds?

(Stick-on thermometers are frankly useless.  You can get inexpensive indoor/outdoor thermometers with remote probes at places like Walmart).  Double check the cage temperatures.

I'm assuming that this is a leopard gecko.  A pale color in leopard geckos usually indicates that the animal is about to shed.  A darker color indicates that the animal is cold or stressed (or sick).  

Make sure that he has a good humid hide so he can hydrate and shed easily.