If you've ever bought hair dye, you know it comes with instructions suggesting that users do a patch test where a couple days before they plan to dye their hair, they put a small amount of the dye on their skin to see if they have any kind of allergic reaction. Most people only open the box when they plan to dye their hair so they wind up ditching that step because what's the worst that can happen - a little irritation? Well one 19-year-old from France named Estelle is wishing she had taken the time to do the allergy test because skipping it nearly killed her.

The teen picked up a well-known brand's hair dye at her local store and while she did do the allergy test, she only waited 30 minutes instead of the recommended 48 hours before doing the dye job. According to Le Parisien, shortly after she finished applying the color, her scalp started to itch, then her entire face began to swell.

Antihistamines didn't help and she said that her forehead had "doubled in volume" and her "head was like a light bulb." She rushed to the hospital where they gave her more medicine and sent her home, but the reaction worsened. Her tongue swelled up, making breathing difficult, so she returned to the hospital where she was admitted. They diagnosed her as having an allergic reaction to PPD, a chemical that is banned in makeup but allowed, and very common, in hair dye.