The 34-year-old singer had earlier said that she had broken her wrist after the fall.
In a post to her fan club members, the singer revealed that the incident also caused severe cuts to her face, reported Entertainment Tonight.
"There is also another part of the story that I haven't been ready to talk about since I have still been living it and there has been much uncertainty as to how things will end up. It's crazy how a freak random accident can change your life," wrote Underwood.
The singer said the accident left her unable to perform at the Country Rising benefit show held at Nashvilles Bridgestone Arena.
"I honestly don't know how things are going to end up but I do know this: I am grateful. I am grateful that it wasn't much, much worse. And I am grateful for the people in my life that have been there every step of the way," Underwood wrote.
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