The owner of lingerie brand Ultimo said she was "petrified" after she discovered a lump in her breast, but ignored the problem for six months.
The Glasgow businesswoman said she shocked herself by ignoring the potential symptom of breast cancer, and has urged women to get themselves checked out after being given the all-clear yesterday.
She said: "I help so many Breast Cancer charities, so it's shocking how I ignored a lump for six months.
"Like many I was petrified. I can't describe the feeling of fear."
Michelle received treatment from consultant breast surgeon Dr Richard Sainsbury, of the London Breast Clinic, where tests revealed she was suffering from cystitis.
She thanked the surgeon in a post on her Facebook page.
She said: Results back today - cystitis drained with a needle, all clear and very healthy breasts."
The cancer scare is the entrepreneur's second brush with the disease. Last year she underwent surgery to remove a cancerous mole from her shoulder.
More than 45,500 cases of breast cancer are diagnosed every year in the UK, usually in women over 50 who have reached menopause.
In a message to other women Michelle said: "Girls, please don't do what I did and ignore it. Act fast and always check your breasts."