4 wire measurement for milliohms resistance problem

I'm working on a project where I need to measure down to milliohms resistance. There will be around 12v and up to 80a across the unkown resistor(resistance wire) when a switch is depressed. Right now I'm using a shunt monitor and parallel shunt resistors. It works, but there's potential for a direct short. My solution so far has been to use a fast comparator. Haven't tested that yet, but I would like to check for a short before there's any high voltage/current across the unkown resistor.

The solution seems to be to use a precision constant current source with an In-amp to read the voltage drop across the unkown resistor and amplify it enough to read it accurately. I really like this idea, but the issue is the traces to read the voltage drop across the unkown resistor will always be there.

Is there any way to use 4 wire measurement in a circuit where there will also be 12v/80a going across the unkown resistor?

Your sensor amp will be a much higher resistance than the resistor that has 80 amps flowing through it, so I would guess the resistance of the pads/traces for the the amp will not contribute much error.

If the "milliohm" resistance heats up, its resistance may change rather dramatically.
Why do you want to use such high currents?

I need it to read around .1Ω+ and down to the milliohm accuracy would be awesome. It does heat up, but it's reading ok now using the shunt monitor and a shunt resistor. It's a high current personal vaporizer. I'm switching the low side with an NFET. It's basically an RMS voltage regulator that only runs about 100hz using a 3s lipo pack that's rated for what I'm doing. Already using it and it's working great. The only issue now is over current protection.

I'm testing the comparator idea tomorrow with the shunt monitor, but I don't know if it's going to be fast enough to stop anything from getting damaged. I'm thinking of using the output from the comparator to switch the gate of a PFET to cut off the PWM signal as fast as possible and having the same trace going to the MCU to enable an interrupt. Sound OK? Says output pin is 3.2ma max, so I'm not really sure about that. I'll try with a current limiting resistor and see what happens.

I'm new to electronics, so if you have a better idea, I'm all ears. Thanks for the replies.

You can purchase a know value resistance to the accuracy needed then use it as a standard when comparing it to unknown values.