But when she decided to have the lump cosmetically removed, a biopsy revealed that it was actually stage-four malignant melanoma, Nine News reports.
She called her boyfriend Ben Debono—who later became her husband—with the heartbreaking news.
"She rang me up and she was all hysterical, she was really upset and worried, you could tell in her voice," Ben told 60 Minutes.
"She knew straight away something was wrong."
After having the mole and surrounding lymph nodes taken out, Leah was told she had a 30 percent chance the cancer would come back.
During regular checks, she was told she was fine. But a month after getting married in October, 2016, Leah started suffering headaches and nausea. Her GP assured her it was likely post-wedding stress.
When she collapsed at work, doctors then discovered the cancer had come back.
“At the time of our wedding she was riddled with cancer. She would have had a brain tumour at that stage as well,” Ben told 60 Minutes.
After a brave battle in hospital, Leah died just three months after her diagnosis at age 29, with cancer in her brain, liver, lungs, spleen and bones. "I was holding onto her until the end,” her husband recounted.
“We watched her take her last breath. You don’t ever want to have to go through something like that, it’s really cruel,” her father Lex also shared.
A year on from her devastating death, Ben has dedicated himself to spreading awareness about melanoma. He and Leah’s parents are still questioning how the 29-year-old's condition was overlooked.
Ben's potentially life-saving advice for all Australians? “Trust your instinct and get a second opinion, get a third, get a fourth.”
This article originally appeared on Marie Claire.