The sight in one of Hunsar Suwannachai's eyes has already gone and doctors fear the other may go soon and could spread to her brain.
She is now considering suicide because she cannot take the severe pain anymore.
The 27-year-old was just 14 when she was diagnosed after she found a small lump on the roof of the mouth.
After a biopsy, a rare form of cancer known as CA Hardpalate was discovered.
The lump was then removed with a series of treatments including chemotherapy and radio therapy.
Over the next four years Fifa suffered pain in the area but doctors tried to play it down believing her to have imagined it.
However, the lump had returned - accompanied by bleeding from her nose and mouth.
Hunsar is now desperate to find a cure after chemotherapy failed and doctors warned that she has limited time left to live.