OK, we progress.
Clearly there is little threat to the canister and your immediate environment, given the temperatures sensed by your hand.
Now, the temperature of the stove body. Your skin has a very abrupt response to anything over 40 C. Just 50 C could have this effect of intense pain. A protective response you see.
Can I suggest you repeat all the measurements with the stove cold and then after running the stove for, say, 3 minutes and then turning it off. Measure the stove body first and quickly before its temperature changes by much. It is not really abnormal for the stove body to get hot – that is one of the reasons they put a long wire handle on the needle valve. Then move on to the other 3 positions.
This will give us 9 temperature readings: ambient via conventional thermometer (not the IR unit), plus cold and hot for each of the 4 positions.
Cheers