Cannon Cribb has one helluva "tattoo" but it's not something he wants to last forever.

The Australian 5-year-old recently returned from Bali where locals painted a Henna tattoo of a dragon on his arm.

But what the boy's parents assumed to be a harmless temporary tattoo turned into a nightmare.

The tattoo wore off completely. But two weeks later, the area where it was applied welted into the shape of the original image.

The family now fears Cannon will be left with a life-long scar.

Doctors believe the paint used on the boy's arm contained paraphenylenediamine, a chemical found in hair dye, photocopying and printing inks, as well as temporary tattoo paint, oils, greases and gasoline.

The chemical has been known to cause allergic reactions in some people including contact dermatitis — an itchy skin rash, and chemical burns.

Cannon's injury is being treated as a chemical burn, requiring his mother Leiona Cribb to clean and bandage it several times a day and apply a steroid cream.

"It looks as though someone has branded him with a red dragon," said Cribb. "I really hope it doesn't scar. We're hopeful, but it's the whole length of his arm; a huge dragon."

Henna tattoos were made popular in the 1990s by celebrities like Madonna and Gwen Stefani. They are now a popular attraction at festivals, carnivals and fairs.

Click here to read more at goldcoast.com.au.