How do I make sure I don't overheat my teflon pan?
To best check temperature, you need a thermometer, and if you can, use a non-contact thermometer (infrared thermometer).

Teflon start degrading at around 260 °C (500 °F).

So check the pan temperature, adjust the heat of your range (electric, gas...) so that the temperature stay below that.

If you want to use high temperature for some applications, then invest in a carbon steel pan or cast iron pan or a stainless steel pan

PTFE Safety