While the brand investigates the issue, dermatologist Hadley King, MD , strongly urges customers to be vigilant when it comes to monitoring ingredients and how your skin reacts to new products — and to ignore the popular myth that when a product is burning it means it's working . "When a dermatologist uses an in-office chemical peel, they closely monitor the patient’s skin to see how it is reacting," she tells Refinery29. "The danger with these at-home masks is that you’re using them without expert supervision and you can’t see how the skin is reacting because the paper mask is in the way."