As if she didn't have enough to worry about with her upcoming 90-day jail sentence and lack of a lawyer to represent her, troubled actress Lindsay Lohan is now engaged in a nasty Twitter feud with legendary insult comedian Joan Rivers.

The back-and-forth began on Friday, when Rivers Twitter-slammed Lohan, writing that the 24-year-old is "so dumb" that her "idea of being sworn in is cursing at the judge." In her inimitable style, she added, "Lindsay Lohan said she wouldn't mind being under oath because she thought Oath was a Norwegian ski instructor," as well as "I was just reading about the new Lindsay Lohan diet, which is all liquid. 80 proof," and "Lindsay Lohan had 'F--- you' painted on her nails. What people don't know is that the judge had 'Eat me you party skank' painted on hers." The latter referred to the now-infamous profane tattoo Lohan had on her fingernail during her recent probation hearing.

"Joan Rivers and her 'stargument' make me believe that she and Michael Lohan are a match made in heaven," Lohan tweeted in response on Tuesday, taking a double shot at the comedienne and her own estranged father, who has said he believes Lohan needs serious treatment for her substance-abuse issues.

"All he needs is her botox doctor. 'Dr.' Drew — any ideas? Botox rehab reality show?" she followed up, adding a third victim to the feud by taking a shot at "Celebrity Rehab" star Dr. Drew Pinsky, who recently told RadarOnline that Lohan would do better in his care in a yearlong residential treatment facility than in jail, which he fears will "harden her."

Swinging at all her detractors, Lohan wrapped up by quoting none other than the G-Unit General. "In the words of 50 cent ... You shouldn't throw stones if you live in a glass house and if you got a glass jaw, you should watch yo mouth."

Pinsky tweeted on Tuesday, "Thanks @lindsaylohan sounds like a terrific plan! Actually happy to see you have retained your sense of humor despite your circumstances," adding a thank you to his fans who defended him in light of Lohan's use of quotes around the veteran addiction specialist and physician's "Dr." title in her tweet. Rivers responded to Lohan's barbs on Wednesday morning (July 14), (), writing "Samantha, Lindsay ... you're welcome!" and then posting a link to a Celeb TV item report suggesting that the comedian's slams had gotten Lohan and ex-girlfriend DJ Samantha Ronson back together over the weekend after nine months apart. The report alluded to a Tweet from Ronson that read, "Hey Joan Rivers — you have collagen older than Lindsay, pick on someone your own age. Oh wait, I guess people that old can't hear." Lohan expressed her appreciation on Saturday with a Tweet to Ronson that said, "thank you. ;)." Lohan is slated to report for her jail sentence on July 20.