The "Herbie: Fully Loaded" star was ordered last month to wear the anklet, which detects alcohol in her sweat, after missing probation hearings related to drug and DUI arrests.
"The waitress has a history with actor Doug Reinhardt, and Lohan was hanging out with him. She was jealous, and out of nowhere, the waitress punched her in the face!" the insider says.
"Doug didn't want any part of it and went to the other side of the booth. Lohan ran out."
Lohan confirmed the incident."A waitress just hit me -- punched me for no reason," Lohan said in a Twitter message around 1 a.m. West Coast time.
The night didn't get much better from there for her.She then decided to go to a party at the nearby Rockstar House and ran into the waitress for a second time.
"Lohan showed up and cried because the waitress was there as well," said another source. "Some birthday."
Last month, Lohan missed a date in Judge Revel's courtroom because she said her passport had been stolen while she was at the Cannes film festival in France.Watch her: