A few days after she began her new skin care regimen — toner, moisturizer, serum and facial mist — the skin around 13-year-old Leora’s lips became red and dry. A couple days later, the rash turned yellow and crusty. “I was touching it because it was really itchy, and then I think it got infected,” said Leora, whose family requested her last name not be published for privacy reasons, given that she is a minor. A dermatologist prescribed Leora a medication to alleviate irritation and advised her to stop her skin care routine and apply petroleum jelly until the rash cleared. Then came a discussion that dermatologists say is increasingly common:…