You scrub your scalp with your fingernails
A good scalp scrub can feel refreshing, but you’re actually doing more harm than good if you use your fingernails. “Your fingernails can scratch the scalp and even cause flaking,” says Sandy Johnson, MD, of Johnson Dermatology in Fort Smith, Arkansas. Instead, use your fingertips to work up a lather. It’s also important to avoid aggressively rubbing strands of hair between your hands, which can damage it and cause split ends, she says. Be sure to stop these other hair washing mistakes you didn’t know you were making.