O'Connor, 46, discussed her new look on her website in a post titled, "Face Tattoo," after first publicly revealing it at the concert last weekend.
"Brendan Quinlan.. 'It's what it is' .. Un ange passe ;)," she wrote, referring to the French expression meaning "awkward silence."
"There's a bottle of Agent Provocateur in someone's room that Belongs to me," she added.
O'Connor did not elaborate on who Quinlan is or why she decided to immortalize him by having his initials penned on her cheeks.
2014: The Year in Fashion [PHOTOS]
Jason Aldean to extend Burn It Down Tour