Rachel Bulmer dyed her hair black for Halloween but the reaction left her face swollen, she could barely hear and feared she was about to die.

The 27-year-old, from Halton in Leeds, carried out the recommended skin allergy test 48 hours before using the L'Oreal product, which is advertised by the Girls Aloud star. The test was negative.

She said: "It's nearly three weeks since I dyed my hair and I'm still in absolute agony. I'm so angry every time I see that Cheryl Cole advert on TV telling me to use L'Oreal 'because we're worth it'. I don't feel like I'm worth it, I feel completely worthless," she added.

"I only wanted to dye my hair for Halloween to make it look beautiful and shiny like Cheryl's, but it ended up falling out in clumps. I definitely don't feel as glamorous as Cheryl. I feel disgusting, because I've got scabs on my head and burns on my skin.

"I'm too ashamed to go out because I have to smear myself in cream to cool my skin and I can't stop scratching.

"I feel like I'm a prisoner in my own home."

She was prescribed antibiotics and steriods after going to hospital.

A L'Oreal spokesman said extreme reactions were rare.

He said: "It is vital to carry out a skin allergy test 48 hours before using the colourant each and every time, following the instructions exactly, which are clearly displayed on our packaging."