I'm seriously beginning to lose it. I'm devoting more time to this snake than anything.

I bought a zilla temperature controller 1000 watt. Seemed to kinda work with my other heating pad, but the heating pad didn't get hot enough. So I got a zoo med heating pad. Plugged it in, and it isn't maintaining consistent temperatures at all. I put it on 90, and the heating pad goes to 110 degrees. I lower it to the point that, that red light goes off which is before 90, and it lowers it to 85. I don't know what to do, and I'm getting extremely frustrated...