Petrie made sure she was tested and has been "nervously waiting" for the biopsy results, which arrived today.
The mole was confirmed to be skin cancer, but Petrie said it has all been removed. She has been urged to go back for much more regular checks in the future.
"We are all preoccupied and distracted and anxious about a pandemic, but it's also important not to forget about things like mammograms, like skin checks, like every other normal health check you would worry about.
"For me, it's been a huge wake-up call."
Petrie acknowledges it can be hard to prioritise checks when so often they have to be rebooked due to Covid-19 restrictions. But she said the effort is worth it.
"If nothing else, I hope it serves as a good reminder to all of us to make sure we do stay on top of these health checks because Covid-19 will end, and we still need to be around for our families."
Cancer Society spokesperson Shayne Nahu said: "It's really good news Wendy picked this up.
"Our biggest recommendation is that people know their skin and self-examine on a regular basis.
"Roughly every month or so is useful and having people help when you can't see things, like on your back."
Nahu said it's important to look for moles that are changing in colour, shape or size, and if you're worried, to book an appointment.
"Start with your GP or skin specialist, and they will be able to get the next step in diagnosis.
"The majority of cancers are self-identified. It's really important to be vigilant in our skin in the first instance, and then follow up with a clinician."
