Your patients often shell out hundreds, and sometimes thousands, of dollars a year on skin care products to improve the look and feel of their skin. This may include everything and anything from anti-aging serums to acne medications.

But are they using these products correctly?

Maybe not, says Philadelphia dermatologist Susan C. Taylor, MD, in a press release.

“Medications or treatments should be applied directly after washing your face,” says Taylor in a press release. “This ensures that the medications or treatments are properly absorbed by the skin. Otherwise, people may think a product isn’t working because it’s applied in the wrong order.”

According to Taylor, here’s the correct order for applying skin care products:

1) Wash your face. Use a gentle cleanser and gently pat dry.

2) Apply medication or treatment. If you are using a medicine or other treatment on your skin, you should apply this right after cleansing unless otherwise recommended by your dermatologist. When applying any cream around your eyes, use your ring finger, as it is the weakest finger and will not pull too hard on this delicate skin.

3) Apply moisturizer and/or sunscreen.

4) Apply makeup, if desired.

“It’s important for people to know that using several products at the same time may not only negate the benefits of each product but also irritate the skin,” she says. “Using too many products may cause redness, stinging, and dryness of the skin, especially if an anti-aging product is included.”