Losing a contact in your eye, having an eyelash linger, or accidently getting shampoo beneath your lid are all unpleasant feelings that most of us have experienced at one point or another. Fortunately, the irritation is only temporary. But imagine what you thought may have been an eyelash turns out to actually be a worm wriggling around. This was the reality for a teenager in Mexico.

The unnamed 17-year-old boy began to feel increasingly intolerable pain in his right eye. His vision also quickly declined, to the point where he could only see hand motions. After three weeks of dealing with the pain, he decided it was time to seek out a doctor, according to his case published in The New England Journal of Medicine.

An eye examination revealed a flatworm, that was 3 millimeters (0.12 inches) long and 1 mm (0.04 inches) wide lingering in his eyeball. If that’s not enough to make you squirm, hearing how the worm was living might just do it. 

The worm comfortably set up home, even creating holes in the teen’s iris as it moved around. The worm was “moving freely in the eye,” Dr. Pablo Guzman-Salas, who treated the patient, told Live Science.

Curious what his eye looked like? Here's a video and photos.

He suffered from serious eye damage to multiple parts of his eye, including the retina, cornea, and iris.

In order to remove the worm, it was necessary for the boy to undergo surgery. The doctors successfully removed it “in multiple pieces,” according to the case report. Sadly, six months later his vision had not improved.

But, how did the worm get there in the first place? His doctors weren’t quite sure considering the boy didn’t report eating any foods that could have exposed him. The teenager also said he didn’t swim in lakes or other water--a common cause of infection. His bowel didn’t contain any eggs or parasites either. Guzman-Salas, who at the time was an ophthalmology resident at the Institute of Ophthalmology in Mexico City, said this was the “first and only” time he’d witness this type of case.

A U.S. eye doctor told CBS, it’s not typical, but it does happen.

"This is a rare, but well-known -- to ophthalmologists at least -- cause of vision loss," said Dr. Jules Winokur, an ophthalmologist at Lenox Hill Hospital in New York City.

"Animals such as dogs, raccoons, skunks, fish or frogs can carry the parasite, and people can get infected either through ingesting the eggs or through contact with invasion through the skin," he said.