Dieu-Nalio Chery, the AP photographer, was treated and released from a hospital in the capital of Port-au-Prince after he was apparently struck by bullet fragments from a gun fired by Sen. Ralph Fethiere.
Chery is expected to undergo more treatment this week to remove an object from his jaw.
Another man, Leon Leblanc, a security guard and driver, was also injured, The Guardian reported.
The chaos erupted as senators met to confirm the appointment of Fritz William Michel as the new prime minister.
Fethiere, a senator from the north of the Caribbean nation, told Radio Mega he was defending himself against opposition demonstrators who rushed toward him and his entourage.
“I was attacked by groups of violent militants," he said, according to the newspaper. "They tried to get me out of my vehicle. And so I defended myself. Self-defense is a sacred right."
Chery was not involved in the protests and was wearing body armor with "PRESS" displayed, according to witnesses. Fethiere said he did not know a journalist was present.
Haiti has seen several demonstrations against President Jovenel Moïse and the government, exacerbated by a crippling fuel shortage and soaring inflation.
Many have called for Moïse to resign. Michel's nomination has also divided Parliament, with some lawmakers involved in violence against one another as tensions rise.
Monday's confirmation vote was eventually canceled. It wasn't clear if Fethiere would face criminal charges.