Sonia Bibi, 20, was admitted to hospital last month, where she told police that her former lover Latif Ahmed had doused her with petrol and set her alight after she turned down his proposal.
Medical staff had originally said she would recover, but a doctor in Multan’s Nishtar hospital told AFP that Bibi’s injuries had become infected and that she died on Tuesday morning.
About 45 to 50 percent of her body had been burned in the attack, doctor Naheed Chaudhry, the head of the hospital’s burns department told AFP.
The incident took place in a remote village of Multan district in central Punjab province. Police have arrested the 24-year-old suspect.
Bibi had told police that she had fallen out of love with Ahmed, and preliminary investigations suggested he had set her on fire “after she refused to marry him”.
Hundreds of women are murdered in Pakistan each year in cases of domestic violence or on the grounds of defending family “honour”.
The Aurat Foundation, a campaign group that works to improve the lives of women in Pakistan’s conservative and patriarchal society, says more than 3,000 women have been killed in such attacks since 2008.