On the beauty horror story spectrum, there's "harmless" at one end and "hospitalization" at the other. Bad haircuts, over-plucked brows, and painful bikini waxes aren’t ideal, but they're not the end-all. Developing a dramatically swollen head as a reaction to hair dye, on the other hand? Not quite so innocuous. Last December, two days after getting her hair dyed at a friend’s salon, Mish Whalen woke up with a big head. And not the kind you get from thinking too highly of yourself, or suddenly finding yourself the President of the United States — Whalen literally had an enlarged head. "There were no problems during the visit. I had my hair colored on a Saturday and I was fine the whole next day," Whalen wrote on Today , where she’s a senior multimedia editor. “But 24 hours later, my head started itching really badly everywhere — my scalp, my forehead.” The next morning, her head was red, itchy, covered in hives… and huge. Whelan rushed to her doctor, who confirmed that the swelling was caused by an allergic reaction to the chemicals in the hair dye. Turns out that there’s some validity to the "patch test" recommendation, which is meant to confirm whether you’re not allergic to what you're about to put on your head. Whelan says the simple test could’ve saved her the trouble — and the trauma. After several days on a combination of Benadryl and steroid pills prescribed her doctor, Whelan’s head returned to its natural size. Fortunately, she’s fine — but if her story isn’t enough to scare you into taking the patch test process seriously, we don’t know what will.