I think the dullness in the eyes could certainly be a cue that the animal is going to shed. Remember BEL's do have eye issues. As far as the high humidity, as long as it's coupled with adequate ventilation (air holes) in the tub and not impeding or prolonged you should be ok. Don't worry too much about the frequency of the shedding bc they shed when they need to. It's more important to offer the animal proper husbandry numbers. That way you can be reassured you are on track. Dehydration doesn't sound like a issue here.