To get my humidity up I spray a couple times a day...just make sure when you are spraying you are not making her substrate too moist. You don't want her lying in moist substrate because that can cause skin sores...I try to spray the plants and stay away from spraying the substrate. I also cover 3/4 of the top of the tank with a towel to keep the moisture in...this can help increase humidity...also adding another water dish can help. To check for mites...run a wet paper towel over her...if they are mites, you will see little black spots on the paper towels...you can usually see them moving.

Looks like she might be an eastern garter to me...can we get another close up pic of her whole body?