For the last ten years of her life, twenty-five-year-old Maria Sylvia has lived with a “cool” brown stripe underneath her thumbnail.

The “cool streak” was a point of pride for the young woman until she learned the truth about it through a viral TikTok video.

Sylvia first noticed the mark on her thumb when she was a sixteen-year-old girl and believed it was a simple mole on her nailbed – however, nine years later, she was diagnosed by a doctor with a rare form of skin cancer that occurs under nails called subungual melanoma.

Sylvia shared her news with friends and followers on TikTok in a video that has amassed more than nineteen million views in just two weeks.

And more and more people continue to watch her video to learn about subungual melanoma and the danger it can pose to someone who has it.

“Me: Having this for ten years, thinking it was a cool streak in my nail,” she wrote as an on-screen caption. “It’s cancer.”

Because so many people were interested in her post about the skin cancer growing underneath her thumbnail, Sylvia decided to share a series of updates in the form of TikTok videos.

She explained that she first noticed the streak in December 2012 when it was very faint. However, it got darker over the years until she finally realized that she was dealing with a rare form of cancer.

“I had seen doctors. I was in and out of doctors’ [offices] all the time. I was an athlete, so I was getting physicals every year,” she said.

“No one really noticed it until one time a doctor did notice it.

This was probably circa 2014, and they were like, ‘Oh, that’s odd, but you don’t really fit the demographics, so if it just grows any bigger, go and see a doctor.’ So, of course, by then, I am pretty sure that it already grew to its fullest extent.”

Because she never had a problem with the “cool streak” under her thumbnail, she never sought any care for it.

“I didn’t have any pain with it, so I just figured it was a mole because that’s what they told me, that it was most likely a mole in my nailbed,” she said.

Fortunately, a friend urged her to get a biopsy. The result was cancer. It was stage 0, which meant that the cancer had not yet grown deeper than the top layer of her skin.

“I was informed that this cancer can stay in situ (also known as stage 0) for 10-13 years before hitting stage 1,” she told Newsweek. “I felt relief that I got it looked at when I did, but I knew there was more to come for getting rid of this cancer.”

Now, Sylvia is encouraging everyone to get screened for cancer.

“I think some people are afraid to confront the possibility of having cancer and facing their mortality,” she told Newsweek.

“The biggest thing I have urged is to put your mind at ease and follow through with seeing someone. If this is caught early, it is very curable, and having a wonky thumb for a month or two is better than not having one at all.”