After five years of osteopathy, diet management, acupuncture, reflexology, homeopathy and paracetamol, I'd wrestled my headaches down from three a week to one every fortnight. Then one day I tried a beauty treatment where my face was injected with carbon dioxide intended to dramatically improve the complexion. It may have been chance, but the said treatment coincided with some of the worst headaches of my life. I felt as though a bonfire of poisonous waste had been started in my shoulders and the hot, revolting fumes were trapped in the crown of my head. I had never felt scared by my headaches before. Now the thought of getting on a plane made me want to cry.