Beautician and Vamp Beauty Studio owner Sheree Mills said she had performed the treatment thousands of times over the past seven to eight years and had never seen a similar reaction.
The woman told Ms Mills she had sensitive skin and asked if there would be any swelling or redness after the procedure as she was graduating as a nurse the next day.
"I said it was highly unlikely but there's always a possibility but if she was concerned she shouldn't have had it before the graduation. I've never had any problems before," Ms Mills said.
"It's really, really unlikely. I did tell her before the treatment it's highly unlikely but she just falls into that highly unlikely."
The Gate Pa woman said the procedure was slightly painful, particularly when Ms Mills applied glycolic acid.
"When I looked in the mirror afterwards my face was really red. I went to do some errands and when I looked in the mirror again it had started to go really dark," she said. "I had to spend over $100 to buy make-up and oil to put on my face."
She took the week off work and has been too embarrassed to go out.
"When I was walking through Bayfair people were staring at me. I haven't gone out in public, I've been isolated at home. It's embarrassing."
Ms Mills said she noticed some swelling in the area down the side of the woman's cheeks during the treatment but the rest of her face was undamaged.
"I can't understand why. The only thing I can think of is that her skin is really delicate in those areas but there was no signs of delicacy," she said.
Ms Mills applied glycolic acid to the rest of the woman's face but took care to avoid the inflamed areas.
"I said, 'I think your skin is really delicate in those areas and it's just taken off a bit of skin. It will heal fine but you need to look after it'," Ms Mills said.
The company had offered to pay for the make-up and oil she bought and perform other treatments if they were needed once her skin had healed.
"It's never happened before and I hope it never happens in the future."
She was sorry the woman's skin was not looking good on graduation day.
The beautician sent an incident report to the New Zealand distributor of the machine.
The owner of Cassa Bella Beauty and Massage Therapy in Christchurch, Louis Lam, performed the same treatment but said the reaction was a very rare occurrence. The New Zealand Association of Registered Beauty Therapists did not return messages left by the Bay of Plenty Times yesterday.