Rapper Nicki Minaj told authorities she was "struck" in the lower lip by a man ... during a heated argument at a swanky Dallas, TX hotel last night ... law enforcement sources tell TMZ.
TMZ has learned ... Minaj was hanging out at the pool at the fancy Palomar Hotel when she got into a very intense verbal spat with an unidentified man she was staying with.
Nicki told a hotel employee to call police ... while the man went to their hotel room. Nicki followed soon after.
When cops and paramedics arrived, Nicki told authorities their poolside fight continued inside of their room ... and the man hit her in her lower lip.
The man had already left the scene when cops arrived ... but Nicki insisted she did NOT want to press charges. Nicki also claimed she was NOT in a relationship with the alleged attacker.
Cops tell us an incident report was taken ... but no charges will be filed per Nicki's request.
Calls to Nicki's rep have not been returned.