Berg got too close to a flame which was part of the special effects, leaving her suffering from second- and third-degree burns on her left arm and shoulder.
Her costume was briefly set alight when a flame projected from a dragon, part of the special effects in her concert, but Berg said she was able to move her head out of the way just in time.
"I suddenly felt a hellish pain," she said, but added that the adrenaline of performing before her fans made her forget everything. "I just carried on singing."
In a Facebook post, the star confirmed the news. "Now I know what pain you go through when you fight a fire-breathing dragon!" she joked.
However, the 50-year-old singer said she had had "a stern word" with the 'dragon' and that it had promised to behave better in future performances. Berg added that she had been well looked after during the interval, and that although the dress she had been wearing was burnt beyond repair, she hoped that her scars would heal.
Hundreds of fans responded to the post wishing the singer a speedy recovery, with many of those who had been at the concert praising how well she had dealt with the incident.
The incident was reportedly due to technical failure rather than human error. There will be no changes to her Seelenbeben tour, which comprises 30 concerts across the country.