Teen stung by Irukandji jellyfish thought she was going to die

A 14-year-old girl stung by the world's deadliest jellyfish has left hospital two weeks after her brush with death.

Hannah Mitchell was stung on the arm by an Irukandji jellyfish while swimming with her friend Zoe off Dampier, in Western Australia's north-west, on Easter Sunday.

Hannah thought she was going to die and even said her goodbyes to loved ones after she was stung.

All doctors could do was provide pain relief as Hannah suffered repeated spasms.

"It was more than pain, it was enough to think I was dying," Hannah told 9NEWS.

"I could feel my lungs and my heart, everything inside me was like crumbling, it felt like it was crumbling."

She was flown to Perth's Princess Margaret Hospital by the Royal Flying Doctor and her mum Casey said staff saved Hannah's life.

"In all honesty we probably should have put her in an induced coma 24 hours before we did and so there's conversations that need to happen around what to do next time and make sure we are not in this position again with other families," Ms Mitchell said.

Hannah still needs pain medication two weeks on but the family is glad to be through the worst of her symptoms.

"I heard her say in the hospital, 'Mum, can you just let me die? I can't take it anymore'," Ms Mitchell said.

"Not being able to make it better as a parent has been the hardest thing."

The teenager is putting the traumatic weeks behind her and said she is just looking forward to the school holidays.

"I'll definitely be anxious to go back in the water because I nearly died but I don't know, I hope to go back to the way things were and I'm excited to go back to the way things were," Hannah said.