I use papertowel in the tubs, Im wondering how the proper way to take the heat readings is?

do I lift the paper towel and take reading directly from the tub surface, or do I just take the reading from the top of the papertowel?

Im asking because, if I lift the papertowel and take reading its around something like 99F to 104F. But if I take reading on top of papertowel it around 87F