Question

we can clean our face with towel but why not with paper

Answer 1

Cause it is meant to be cleaned with towel. Rather towel is meant to be used to clean the face i.e. wiping, while paper is to writing

Answer 2

hey mate here is your answer->

we clean our face with towel because towel absorbs water , sweat etc..
whereas a paper don't observe

hope this helps you