When the object hit the side of her skull, the famous New York City performer fell to her knees.
Later, with her hands still clutched to her face in evident distress, she has led away from the arena.
The audience chanted “That’s assault” when a video of the incident circulated online.
The assault accusation against the 27-year-old concertgoer was subsequently verified by the New York Police Department.
The singer of such songs as “I’m Good (Blue)” and “Meant to Be” as of late revealed her wounds in a series of Instagram posts on Monday.
Her left eye was bruised, and her eyebrow was slashed. Still, she thumbed up for the camera and wrote, “I’m good” in the photo captions.
Rumor-mill site Her mother was mentioned on Pop Base claiming that the actress had to have three stitches after an accident.
The incident happened as the singer was wrapping off her performance at Pier 17 in New York.
She had earlier brought up a sobbing El Salvadorian fan to sing “I’m Gonna Show You Crazy” and performed an impromptu rendition of “Seasons” at the request of the crowd.
Attendees were shocked by the unexpected turn the event took towards the finale.
“I’m still in shock two hours later,” one Twitter user said. Something flew and smacked her, and I witnessed it. Before I saw her fall, I assumed it was a CD or a piece of paper.
One concert-goer said that everyone had gotten dressed up and was in a good mood since they were coming to the show, but that an “old man ruined everything.”
“Super unsettling ending to an otherwise great show,” said a third viewer. I really hope she’s OK.
Rexha’s next scheduled performance is on Tuesday, June 20 at Philadelphia’s The Fillmore.
On July 28th, she’ll bring the tour to London at Shepherd’s Bush Empire.