United Kingdom, July 18 -- Teddi Mellencamp was "really upset" after she was told she looked prettier with "long hair" before her cancer diagnosis.

The 43-year-old reality star has been battling stage four melanoma - which has metastasised to both her brain and lungs - and she has undergone surgery, radiation and immunotherapy as part of her treatment, which caused hair loss, and Teddi has now admitted a cruel online comment about her appearance sent her into a downward spiral.

She told Glamour magazine: "With the hair, it's weird the things that would upset me. People would write to me: 'Why did you shave your head?'

"I remember getting really upset by it because I'd be like: 'I lost my hair. I shaved the parts that I didn't lose' ......