You know that little warning on hair dye boxes that reads something like “Allergy test 48 hours prior to each application, even if you have already used coloring products before.”

Well, this is what happens if you ignore that warning and discover the hard way that you’re allergic to a chemical called Phenylenediamine (found in 2/3 of hair dyes). 

Redditor JohnTheRevelatorJR posted some photos of his friend’s brother’s nasty reaction to the chemical. 

I had no idea about this. I’ve dyed many a friend’s head in my past with zero regard to the the warnings. I guess I had no idea of the severity. I’ll bet a lot of other people don’t know either.

From what I read in the reddit thread, his swelling has gone down a lot.
 

 

 

 
Images via Imgur

Via BuzzFeed