Face masks (the skincare product, not the protective covering!) are a great way to make your skin feel clean and refreshed, so it's no wonder they're a top beauty trend year after year. 

When NYC-based cosmetic dermatologist Dr. Shereene Idriss, AKA the "Pillow Talk Derm," asked her Instagram followers to share their skin confessions, a common one was about leaving face masks on longer than directed.

SKIN CONFESSION: "I always keep masks on my face for 10 extra minutes."

That's not so bad, right? Actually, it can be, according to Dr. Shereene.

While many people believe that leaving face masks on for longer than instructed will leave your face extra clean and refreshed, the reality is that it can actually have the reverse effect on your skin. 

"Everyone thinks that more is better — and that's not the case," the derm says.

There are different kinds of face masks, including clay masks and sheet masks. Especially with clay masks, which are meant to draw out impurities from your skin, if you keep them on too long the clay can start to draw out the goodness from your skin as well as the bad, she explains.

"It's going to disrupt the pH balance of your skin, wreaking havoc on your skin," Dr. Shereene says. "Same thing with sheet masks, because with time they dry out, and they're going to try to pick up moisture from your skin and the environment. So it's going to leave your skin drier."

If you're guilty of leaving face masks on for too long, the derm suggests trying a bio cellulose mask or a gel mask, which is a little bit thicker and less permeable. "This mask, after you apply your skincare, will help lock in everything and keep you hydrated longer," she says. 

Still, no matter what type of mask you're using, you should only keep it on your face for the time noted in the directions. The longest time a mask should stay on is 20 minutes.