Anne Crossan told a jury on Thursday that the man who scarred her for life was Stewart John Watson, 36, from Polbeth, who denies attempting to murder her in the attack on 4 November 2015.
Miss Crossan, 47, said she had run a bath at her terraced cottage in Polbeth, West Lothian, and was about to get into the water when Watson came to her door at around 11.30pm.
She said he asked to talk to her about her best friend Sharon Christie, who had just broken up with him after a six-month fling.
But when she opened the door, she claimed he showered her with a flammable liquid and set light to it, engulfing her head and neck in flames.
She told the High Court in Livingston: “My hair was on fire; my face, my neck was on fire. I think my throat got a bit burnt as well. I lost quite a bit of my hair and my scalp was all burnt. I was baldy there for a while.”
Two months before the alleged attack, she said she had found out something about the accused and phoned his then girlfriend to tell her. She said he overheard her call, grabbed the phone and threatened to “murder” her.
The trial continues.