I would plug the heat pad back in, grab some wood(2x2) or something that won't melt and jack the tub or tank up an inch to two inches above the heat pad so the snake stays warm until you get the tstat.
Hydrofarms and Repti-temps "work" ok but you might save up for a better proportional thermostat if you like the temps to stay consistent.
I think what you hear about them not being accurate is wrong.
It's an on/off thermostat and all of them go up and down in temperature 4-7 degrees.
Set the temperature on it's upswing and get it to go up to about 97 when it turns off.
It will then drop to 90 to 93 degrees before turning back on and going back up to 97 before turning off again.
Measure the hot spot directly over the heat source inside of the tank/tub.
Good luck!