Lauren Fuller, from Shotts, Lanarkshire, was building a den by a riverbank on Sunday June 28 when the scooped up the invasive plant, which grows wild.
Within 24 hours she had bright red burns on her hands and cheeks – but when her parents took her to hospital, they were told it was just sunburn.
Unsatisfied with the diagnosis, they Googled their daughter’s symptoms and quickly realised she was a victim of giant hogweed.
Lauren may now need skin grafts to repair the damage. Her father, construction worker Russell, 32, of Thornbury, Bristol, said: “It was really, really bad. They put these little gloves on her to cover the blisters and when they took them off a couple of hours later her skin had completely melted.
“Lauren is a tough little cookie but she was crying a lot. She was in a lot of pain and she was really worried about what was going to happen to her hands.”
Lauren was taken to Wishaw General Hospital before being moved to the Queen Elizabeth University Hospital in Glasgow.
Giant hogweed was originally brought to the UK from Central Asia in 1893 and now commonly grows on riverbanks and wasteland.