In a waiting room crowded with relatively minor deformities like cleft palates and webbed fingers, Eng Kheng stood out.

His cheeks bulged as if he was trying to swallow a large pink grapefruit, with sections pushing through his lips.

"He basically has a benign bone growth of his facial jaw bone, the condition is called fibrous dysplasia," said Andrew Cheng, a surgeon visiting from Adelaide.

"It's certainly one of the most severe cases I've seen," said Dr Cheng, back in February.

The huge growth was not cancerous or painful.

WARNING: This story contains graphic images.

Mr Eng said he managed to eat, although it could be a messy process.

Eng Kheng says he was able to eat prior to his surgery, but it was often messy. ( ABC News: Liam Cochrane )

Fibrous dysplasia is a rare condition, but not in Eng Kheng's family — his brother has it and so does his father.

The farmer had pretty much accepted his uncomfortable deformity, until a health worker came to his village to check people's eyesight and made a referral to the capital, Phnom Penh.

The facilities at Preah Ket Mealea Hospital would be considered basic by Australian standards — a crude wheelbarrow by the lift acts as patient transport — but it was the biggest hospital Mr Eng had ever been inside.

Dr Cheng showed him the surgery plan on an iPad, Mr Eng looked bewildered by the high-tech image of his face, with the tissue destined for removal coloured green.

He hoped that the doctors could "heal" him, but had little idea how his face might look after the surgery.

"I wonder about that, hopefully my face is more handsome than before," Mr Eng said.

Doctors regroup after 1970s slaughter

After his consultation, Mr Eng went to visit his brother in the next room, recovering after having a similar but smaller growth removed in the Phnom Penh hospital.

Cambodia's few specialised surgeons are desperately understaffed.

The medical ranks are still recovering from the madness of the Khmer Rouge years.

Between 1975 and 1979, the ultra-Maoists tried to turn the country into a peasant utopia by sending urbanites to the rice fields and killing everyone with an education, including doctors.

Nous Sarom is one of those leading the recovery.

He is in charge of maxillofacial, plastic, reconstructive and aesthetic surgery at Preah Ket Mealea Hospital.

Andrew Cheng, with Nous Sarom, trying out the hardware store drill that "healed a thousand patients". ( ABC News: Liam Cochrane )

Dr Nous shows off a small cordless drill that he bought in the post-Khmer Rouge days from Phnom Penh's Russian Market to use in the operating theatre.

"It's healed thousands of patients," Dr Nous said.

"It's good, it [has] a chargeable battery and you put the bit in and then you can drill to the bone, make a hole and fit the screw and we can fix the patient," he said with a smile, obviously having shocked foreigners with this story before.

These days, the little hardware store drill has been retired, superseded by modern, donated equipment.

Since 2012, Cambodian's International University has run a masters degree in oral and maxillofacial surgery.

Its five students are taught in modules by visiting surgeons, mostly from Australia, Japan and the United States, who cram as much knowledge as they can into one- or two-week courses.

Eng Kheng in a Phnom Penh hospital for a consultation before his facial surgery. ( ABC News: Liam Cochrane )

But cases like Mr Kheng's are too much for Cambodia's health system.

"During the surgery he might encounter massive blood loss and unfortunately, currently blood transfusions in the Cambodian surgical world are unpredictable," Dr Cheng said.

Which is a polite way of saying there would probably be no blood stock and the patient would die.

'I felt like I'd been born again'

In late February, Mr Eng flew to Adelaide for his surgery.

His trip was made possible by the fundraising of Walk on Water, pro bono care from Ashford Hospital and the local Cambodian community.

"In Australia they cared for me so well," Mr Eng said.

"I was offered meals all day — breakfast, lunch and dinner, even coffee.

"They took me to the beach, to the mountains and the shops."

Acclimatized to Cambodia's intense tropical heat, Mr Eng wore a thick jacket, scarf and beanie to hospital, even though it was late summer.

"The operation was painless, I just fell asleep [and] dreamed I was in a big plane," he said.

The new experiences in Australia and the warm welcome he received put him in a philosophical mood before the operation.

"I thought, 'If I die, I die', but then I woke up and I was still alive," he said.

"When I woke up and saw my face it looked beautiful. I felt like I'd been born again."

Reason to smile

Mr Eng is now back in his village in Kampong Cham province.

The difference to his face is extraordinary.

Eng Kheng at his home in Kampong Cham province, four months after his facial surgery. ( ABC News: Liam Cochrane )

There is some scarring and he has to wear dentures, but his jawline is normal and he can smile.

"I don't want to change much, just keep farming sugar cane and vegetables," he said.

His relatives gather under the wooden stilt house and tease him about a female admirer in the village.

But after decades as a bachelor, Mr Eng is not ready for romance just yet.

"Someone said that if I got married, he'd give me $3,000 [for the wedding] but I didn't take the offer," he said.

His main emotion for now is gratitude, for the lucky discovery by the visiting health worker, and the generous fundraisers and Cambodian diaspora, but especially for the surgeons.

"I want to thank the doctors," he said, with a smile those doctors made possible.