Soth Rey was working in a Siem Reap massage parlour to help support her parents and three younger siblings when she contracted an unexpected illness.

According to Rey’s 20-year-old sister Soth Borey, the young woman fell ill with a sinus infection in December. They brought her to a doctor in Siem Reap who said she had the flu. But weeks later, ulcers developed in her nose, and the doctor opted to pull some of Rey’s teeth, Borey says.

It’s unclear exactly what type of medical treatment Rey received, and her sister says she doesn’t remember the doctor’s name. But when Rey didn’t recover, she went to the local Kruu Khmer, a traditional healer who spit and blew on the ulcers for a month. The illness persisted, and then Rey’s face began to disintegrate.

Only two days ago, when – at death’s door – Rey was checked into a new hospital in Phnom Penh, did it become apparent that the 18-year-old was suffering from a rare case of necrosis, a form of rapid cell degeneration that has transformed the right side of her face into a wide, gaping hole that exposes her teeth and bones. Her nose and right cheek have vanished entirely, eaten away by the illness. It’s unclear whether her right eye is still intact, but her lower eyelid has disintegrated.

Now she is fighting for her life.

Rey would have died if it weren’t for an online plea. A friend posted an emergency message in a Facebook group, and Yulia Khouri, a Phnom Penh resident, stepped in and offered to pay for the girl’s medical treatment. Rey is now in Phnom Penh’s Sen Sok International University Hospital, where she is being treated by a team of doctors fighting to stop the necrosis from spreading.

When she arrived at Sen Sok she weighed 38 kilograms, had a high fever and an open wound that smelled worse than a morgue, the doctors said.

“She’s stable now, but it’s so serious. The situation could turn 180 degrees at any moment,” said Dr Ivan Matela, one of Rey’s doctors. She is suffering from pneumonic septicemia and is malnourished, he adds.

The doctors say they’ve never seen such a serious case of necrosis, either in Cambodia or abroad. But the general population’s poor understanding of general health and hygiene is a serious problem in Cambodia, and may have exacerbated the case.

What’s more, most of the country’s doctors do not give patients information about the treatment they’ve received. Patients often leave the doctor without copies of their X-rays or blood tests, making the job especially challenging for the next doctor they visit, Matela says.

Khouri, meanwhile, is working tirelessly to raise funds for Rey’s medical expenses, which include antibiotics, blood transfusions, and a host of other treatments.

“The hospital has been helpful and allowed us to use volunteers for blood donations instead of paying for blood, so that helped with the expenses,” says Khouri, who launched a fundraising campaign on the website Just Giving and is organising blood donations from donors with Rey’s blood type, A positive.

“The amount of goodwill is incredible, but there are also some crooks trying to take advantage of this,” Khouri said. Some local websites have replicated her call for help using their own Wing numbers to receive donations, she noted.

Throughout all this, Rey is conscious of what is happening. When the doctors said she had to cut her hair for hygiene purposes, the young woman grew anxious. A shaved head symbolises death in Cambodia, says Khouri, who opted to recruit a volunteer hairdresser to give Rey a stylish pixie cut.

Tatiana Turobova, another doctor treating Rey, says the patient is able to feel pain. She must be given high doses of painkillers, including morphine, when the doctors clean her wound, Turobova explains.

What’s clear is Rey could need years of treatment, including expensive reconstructive surgery.

“If she does survive, there will be a very long recovery process,” Matela says. “This is just the beginning.”