There are two kinds of hair bleaching that you can have done at the salon — "on-scalp" and "off-scalp" bleaching. "On-scalp" refers to a bleach application that reaches all the way up to the root of the hair, while "off-scalp" refers to bleach that is not applied to the scalp at all. If you want something like Kim Kardashian's Met Gala platinum, you'll need an "on-scalp" treatment. Considering her look made people wonder if her hair would fall out, "on-scalp" bleaching is the kind of extreme coverage that can lead to safety complications and the risk of a chemical scalp burn. 

According to a 2012 report published in Annals of Burn and Fire Disasters, bleach typically includes H2O2, persulphates, and alkalizers. The article notes that if your hair bleach contains levels of H202 (also known as hydrogen peroxide) above 10%, it can cause scalp blistering. Although many of us don't realize it, the scalp is just as delicate and irritation-prone as the skin on your face. "Typically, a bleach burn is a first-degree burn that affects the outer layer of skin, leaving you with a red, painful scalp. However, you can get a more severe burn that extends beyond the top layer of skin and leaves blistering and swelling," board-certified dermatologist Dr. Nazanin Saedi explained to Seventeen.