Question about using cotton pads when applying toner.

If you look at cotton stuffing, there is a front and a back side; which do you use it for?

I just grab whatever I feel like each day, depending on my mood. If you look at the cotton on mine, the front is like gauze and the back is just cotton. Some products, however, have the same front and back.

In this case, should I use cotton or gauze? Actually, I tried using gauze and it irritated my skin texture, but it also feels like it removes impurities.

What is the correct answer for front and back?

My skin has been red because it was rough, but that is also because I rubbed it with my own power.