But that's exactly what happened.
"What started out as a few heavy nosebleeds turned out to be the most horrifying journey of my life," McHaffie, who is from Wisbech, Cambridgeshire, told the Mirror.
The mum-of-one started suffering from severe nosebleeds in April 2014 which would sometimes last for hours.
After visiting her doctor, she was told that it was probably hayfever and there was "nothing he could do about it".
Between May and June she was hospitalised on multiple occasions after her nosebleeds became so heavy that she had to be cauterised, which involves burning the skin of a wound with a heated instrument or caustic substance to stop bleeding.
Later in the year, after her nosebleeds still hadn't subsided, McHaffie found a small strawberry-sized lump in her right nostril.
By the following month it had grown so large that she couldn't breathe properly.
After sharing her concerns about the lump with her GP, she was advised that it was probably a "common polyp", which is a small growth which portrudes from a mucous membrane.
In November she was referred for a CT scan and then an emergency MRI scan which confirmed she had adenoids cystic carcinoma (ACC).
ACC is a rare type of cancer that forms in the salivary glands in the head and neck.
Since her diagnosis, McHaffie has had half of her face removed in surgery, including her pallet bone, upper teeth, parts of her cheek bone and top right jaw.
Doctors also had to remove bone from her leg in order to rebuild her missing facial features.
McHaffie says that the one thing that got her through the grueling surgery was her three-year-old daughter, Leylah.
"I wanted them to do whatever it took to save me as I don't want to miss a second of her growing up," she said.
She is now recovering at home and hopes that by this time next year, she'll be able to have veneers and her appearance will return to normal.
Since her return from hospital, McHaffie has been spending a lot of time with her daughter who she says has been looking after her - despite it taking a while for her to get used to McHaffie's new appearance and voice.
Writing on Facebook, she said that her daughter had been "really loving and caring".
"She's been amazing," she added.