What a woman thought was a lump on her face that mysteriously moved around from one part of her face to the other and occasionally itched, turned out to be something right out of a nightmare — a parasitic worm.

The bizarre condition that the 32-year-old Russian woman suffered from eventually ended up being a case study in the New England Journal of Medicine. And a latest report published in the journal details the horrifying discovery.

The unnamed woman first noticed the lump just below her right eye. After five days, the lump had moved on the top of her left eyelid, below her eyebrow. Next, the lump migrated to the left side of her upper lip, causing her to have lopsided swelling in that area.

Although she might not have a clue as to the terrifying reality of the migrating lump, the woman did have concerns about her condition and proceeded to take photos of herself every time the lump happened to move. According to the report, she also experienced itchiness accompanied sometimes by a burning sensation in the part of her face the lump moved to.

Finally, when her lip swelled up due to the lump, the woman went to see a doctor and was in for a rude surprise.

The lump in question was caused by a parasite known as a Dirofilaria repens – a long, thin roundworm that enters its hosts through mosquito bites, according to the Centers for Disease Control and Prevention.

“A physical examination showed a superficial moving oblong nodule at the upper eyelid,” doctors who treated the woman, wrote in the journal. “A parasite was fixed with forceps and removed surgically. The parasite was identified by means of a polymerase-chain-reaction assay as Dirofilaria repens, which is a zoonotic filarial nematode.”

"After removal of the worm the patient had a full recovery,” they added.

While there are three types of Dirofilaria that can affect human beings —D. immitis, D. repens (this was the one in our Russian friend's face), and D. tenuis – humans are not considered to be the natural hosts of these roundworms. They typically choose cats, dogs, wolves, coyotes, foxes and sea lions to live inside.

Hence, these parasites cannot reach a point of maturity inside the human body nor can it reproduce. They can, however, literally crawl under one’s skin. So a human infection by one of these worms is always an accident.

But surprisingly, the Russian woman’s case is not one in a million, as cases of people getting infected by parasitic worms are becoming increasingly common in the recent times.

Vladimir Kartashev, a professor of medicine at Rostov State Medical University, who was one of the doctors who treated the woman in this case study, wrote a 2015 study on dirofilariasis – the disease that people get after contracting Dirofilaria. In it, he mentioned that between June 1997 and June 2013, nearly 1,300 cases of dirofilariasis were found in Russia and Belarus, usually in people who lived in the rural areas.

The woman in the latest case also happened to visit a rural area outside of Moscow, Russia. D. repens is not found in the United States.

But tourists who plan to travel to Russia to watch the FIFA world cup this year are advised to always keep insect repellant at hand and cover themselves up if they plan on visiting the rural areas.