My large adult male leopard geckos has some dry patches on the top of his head. He's had it for around a week. He is housed in a 20 gallon long and uses a under heat heater. He has a moist hide that he loves to dig in and he is housed with one other female for breeding purposes, but they were separated temporarily because I want to figure out why his head scales are so dry. He never scratches himself or rubs against things. He acts normal and eats fine. The small black dots in this picture is peat moss when he got it all over when digging in the humid hide.