Pimples come and go—it’s just an accepted fact of life. But sometimes what you think is a pimple can actually be something way more serious.

That’s what Jodie Dominy discovered when she learned that her “stress pimple” was actually a rare form of skin cancer called Dermatofibrosarcoma Protuberans (DFSP).

The 41-year-old mother of two tells Australia’s that’s life! magazine (per The Daily Mail) that she was originally told a bump on her chin was a fatty cyst. “The doctor explained I could have it removed for cosmetic reasons, but there was no harm in leaving it alone. I decided not to bother,” says Jodie in that interview.

But the bump grew, so Jodie asked a plastic surgeon to remove it during a procedure to remove a benign skin cancer on her lip. After it was analyzed, the doctor discovered it was a rare form of cancer.

“Most cases of DFSP have been found on the arms, legs, or back,” Jodie wrote on Facebook. “In Australia, there are only eight reported cases of DFSP, and I am the only one ever to have it on my face.”

Jodie’s doctor told her that the cancer was similar to an octopus—it had long tentacles that spread around the bump and formed deep roots, making it hard to remove. She had to undergo extensive surgery to remove it from her chin, bottom lip, jaw, and left cheek, as well as facial reconstructive surgery.

Not so much for this particular form of cancer, says dermatologist Marie Leger, M.D., Ph.D., an assistant professor of dermatology at NYU. “It is not common—only about 0.8 to five people are diagnosed with it per million people a year in the U.S.,” she says. The problem with DFSP, however, is that the tumors can grow large and can even come back after surgery, she says.

It also causes a tumor in the deep layers of skin, which branch out like roots in a tree, says dermatologist David E. Bank, M.D., director of the Center for Dermatology in Mount Kisco, New York.

Leger says it’s not uncommon for someone to mistake a cancerous bump for a pimple. “I have seen this before in my practice, more commonly with basal cell carcinomas, in which a person will dismiss a bump on their face, chest, or back because they think that it is a pimple,” she says.

But board-certified dermatologist Jill Waibel, M.D., medical director and owner of Miami Dermatology and Laser Institute in Miami, points out that pimples go away. If you have new or old bumps that aren’t healing, are bleeding, change in size, color, or shape, or become painful or itchy, it’s time to get evaluated by a dermatologist.

Leger recommends getting yearly skin checks with a dermatologist so your doctor can spot this kind of thing. But, if you notice something between visits, get it looked at. “Many people mistake things like flesh-colored moles and pimples as cosmetic inconveniences,” says Bank. “However, they should be checked out by a dermatologist to ensure that they are not cause for serious concern like cancer.”