Does feeling a slight taste and sting after using a face cleanser during the day in Ramadan affect the fast, or does feeling the taste of book pages after putting a finger on them and then licking it [affect the fast]?

What has been mentioned does not affect the fast. Tasting something with the tongue without it reaching the throat does not invalidate it. And what reaches the throat or stomach without the fasting person's choice, after it is impossible to expel it, does not invalidate the fast. Your fast is valid, so there is no need for obsessive thoughts.