Using IR thermometer sensor for body measurement

Hello,
I'm new here. I want to made contactless forehead temperature measurement.
I has been test the IR temperature sensor MLX90614 and able to read Ta and To.
This sensor is look like read (To) the surface actual temperature only.
If object come from the cold room will measured as low value (To) because if I touch the forehead feel cold and if object come from the hot environment will measured as high value (To) because if I touch the forehead feel hot.
How to make the measurement on forehead accurate? Is Ta and To can formulated?

thank you very much.

regards

An MLX90614 can only measure surface temperatures (by design). As you correctly recognized the surface temperature of a face usually isn't identical to the body's core temperature and there is no fixed relation between the two temperatures.

How to make the measurement on forehead accurate?

The measurement is probably accurate but the forehead's temperature is only a hint to the body's core temperature but there is usually a quite relevant difference. So if you want a precise body core temperature by measuring the forehead temperature you will fail.

Hi Pylon,
Thank you verymuch