Hailey Bieber is suffering a “pretty bad flare up” of her perioral dermatitis. The 27-year-old model told fans she has been afflicted with the condition – which resembles acne or rosacea – since she was in her late teens, and shared her sympathies with its millions of other sufferers. She said in a TikTok video in which she showed off her irritated skin: “This is something that I have had since I was about 19 or 20, and I know a lot of other people deal with it and struggle with it as well. “I’m having a pretty bad flare up right now so I wanted to share what I use when I’m having a flare up.”…