According to TMZ, Barron was jumped in Miami, Fla. Thursday morning and told police Lohan was the mastermind behind the attack.
Sources who were at the party where Barron was attacked said the hotel heir had been badmouthing Lohan a short time before he was assaulted.
Barron, 24, told police Lohan approached him at one point during the party with a male friend and said, "You talk [expletive] about me to my boyfriend, this is what you get."
Lohan has denied any involvement in the incident, and claims she left the scene as it was taking place. However, TMZ has footage of Barron confronting Lohan after it happened.
After posting a picture of his fractured face on Instagram, Barron's sister Paris pledged to avenge his suffering.
"They both will pay for what they did. No one [expletive] with my family and gets await with it!!!!" Paris commented on the pic.
Michael Lohan, the Mean Girls star's father, told TMZ his daughter was innocent and that several witnesses can corroborate her claim that she left the party early.