When Melanie Williams first noticed a black mark on her thumb, she assumed it was a fungal infection or wart.
But a trip to the doctors revealed that the 36-year-old's mark was actually skin cancer.
The mum-of-one shared an image of her thumb on Facebook, writing: "See that on my thumb? Do you know what it is? It's skin cancer. This grew from nothing in a matter of weeks.
"I thought it was just a fungal infection or a wart. Sadly not. I've been lucky, the cancer hasn't spread and it's being removed next week along with half of my thumb. This may have not been the case if I'd left it and not got it checked out."
She went on to say that she didn't want sympathy from friends and family on Facebook, but simply wanted to raise awareness about the signs of skin cancer.
"Please go and get any changes or growths on your skin checked out, please tell people around you to get checked as well," she said.
"Don't leave it to chance or make excuses! I will be fighting fit in no time but if I'd left it, I may have been losing more than a thumb."
According to the NHS, skin cancer is one of the most common types of cancer in the world. Symptoms of the disease include a change in the appearance of a mole, or a discoloured patch of skin, just as Williams experienced.
Her Facebook post has now been shared more than 115,000 times.
Commenting on the original photo, she recently left an update to those who have been following her story saying she had undergone surgery to have part of her thumb removed.
"I had my op today, but it turns out I may need more of my thumb taken than first expected. I'm due to have more tests done in the next week, so will have to see where we go from there," she wrote.
"Thank you to everyone who shared this post. Totally lost for words (for those who know me, this is rare) on the response it has received. I feel proud of everyone who's shared and taken note because of the awareness it's raised! You lot rock."