there is no self regulating heat pad they all need to be controlled even those that are supposedly not getting over a certain temps actually do.
You have a heat pad you need a thermostat or it will be an accident to happen.
And remember what is warm to you to the touch is often too hot for a hot spot.
For example your body temp is 98.6 therefore a heat pad at 98.6 would feel barely warm to you however the temp would be too high for a BP.
I will direct you back to what I recommended you to go over in one of your previous thread