It’s the stuff that nightmares are made of: You’re coloring your hair, hoping to achieve the perfect sun-kissed effect, only to have it all fall out when you’re finished. No joke, we’ve had the exact night terror. Only for one U.K.-based teen, the horrific results are real.According to The Sun , 16 year-old Courtney Andrews lost gobs of hair — basically from her jawline down — after attempting to ombré her hair with a box of Superdrug Blonde Permanent High Strength Blonding Kit Here's how The Sun reported the story: With the help of her mother, Andrews started the process with a skin patch test to prevent adverse reactions with her scalp. After applying the lightening product, Andrews’ mom says she checked her daughter’s hair every five to 10 minutes for 30 minutes — but the processed hair started feeling hot to the touch."We rinsed her hair and put a comb through and the hair just kept coming away with each brushstroke,” Andrews’ mom, Claire Coles-Morton, said.More than $100 and three hair appointments later, Courtney’s hair has been restored into a wearable style. Still, the article reports that the product's maker, Superdrug, “confirmed that they had not received any other complaints about the kit Andrews used.”So, what the heck went wrong and how can we avoid the same fate?The article reports that while Andrews and her mom conducted a skin patch test, the duo skipped conducting a strand test — something that's advised in the kit and may have predicted an adverse reaction. George Papanikolas , a Matrix SoColor stylist who works with celebs like Naya Rivera and Mila Kunis, says that it’s important to stand test. “Take a section underneath your hair that's inconspicuous and try it first to see how it reacts,” he advises.Superdrug agrees. "We strongly recommend this, as it not only allows customers to gauge the colour results, but also helps to highlight any underlying problems. This is especially important when using a bleach-based hydrogen peroxide product on previously coloured hair,” the hair color maker told The Sun.