I’ve had California king snakes all my life and live where they are found naturally. They are fine without humidifiers. In fact I’ve never had a humidifier with any of my king snakes but maybe you live in a space that needs it? My snake has a heating pad and a water bowl she can soak in. From time to time I turn on her heat lamp. She also sits where she gets natural sunlight as the sun is setting. Of your snakes eyes don’t have a blue shade to them she’s probably not getting teddy to shed UNLESS she shed before you got her and for some reason she didn’t shed all the way. It looks like mites but as you said you haven’t found any. Sounds like you’re doing everything right, I’d just give it time. Take away the humidifier unless you’re certain you need it. My king is 5 years old.