Bali, Indonesia - A mother warned of the dangers posed by black henna after her son had a horrific reaction to a temporary tattoo given to him while on vacation in Bali.

After traveling to Bali for a holiday, an Australian tourist from Sydney decided to get a decorative and temporary henna tattoo inked onto his arm. A number of days later, though, it turned out to be a mistake.

Taking to the Facebook group "Bali Bogans," the boy's mother shared a number of gruesome pictures showing his arm covered in scabs and red, inflamed skin.

"My kiddo got a henna tattoo at Seminyak beach and had this reaction," the mother captioned the pictures, issuing a warning for other beachgoers.

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"It happened about a week later once we got back home thank goodness!"

"It may not happen to you, but just wanted to share anyway," she continued. "It could be his skin, but he’s never had a reaction like this before. It’s spreading but no pain it’s just incredibly itchy."

In the comments, the mother revealed that she had taken her son to a doctor, where he was prescribed cream, antibiotics, and antihistamines to help get everything cleared up.

Commenters on the post pointed out that this is a relatively common problem with black henna and can be really nasty.

Some theorized that the substance was not traditional henna, and included a chemical called paraphenylenediamine (PPD) that is commonly used in hair dye and has been known to give people allergic reactions.

"My daughter had the same reaction years ago," one commenter stated. "She is allergic to PPD, so we found out."