Lindsay Lohan is so desperate to prove to producers that she can be trusted again that she refuses to miss a single day of filming on her latest movie, "Liz & Dick," despite her recent car crash and medical scare.

But Lohan's long hours and stress are making many people worry about the troubled actress.

“Hours after being found [non-responsive] in a Los Angeles hotel room, she was back at work,” a member of Lohan's inner circle tells me. “Of course I’m concerned, but she is strong and needs to show everyone that she is back.”

The 25-year-old was seen on set hours after her publicist confirmed she was exhausted, looking weary as she made her way into her trailer wearing a dark fur coat.

Telling her fans via Twitter that she had worked 85 hours in just four days, Lindsay was not taken to a hospital, but was checked out in her hotel room by paramedics.

“She is a ticking time bomb,” one industry insider tells me. “You know the producers are scared when they call 911 when she doesn’t answer her phone. I’m sure they are asking, what the hell did we get involved in at this point, but they are not exactly making her schedule lighter. This is a tough town. If Lindsay hadn’t been making a movie, who would have called for help? As soon as filming wraps, she will be all alone again.”

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    Lindsay Lohan attends the 2012 White House Correspondents' Association Dinner held at the Washington Hilton on April 28, 2012 in Washington, DC. This was the 98th annual dinner and was hosted by Jimmy Kimmel. (Photo by Kristoffer Tripplaar-Pool/Getty Images)

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    Lindsay Lohan attends the 98th Annual White House Correspondents' Association Dinner at the Washington Hilton on April 28, 2012 in Washington, DC. (Photo by Stephen Lovekin/Getty Images)

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    Actress Lindsay Lohan attends day 3 of the 2012 Coachella Valley Music & Arts Festival at the Empire Polo Field on April 15, 2012 in Indio, California. (Photo by Christopher Polk/Getty Images for Coachella)

  • Lindsay Lohan Probation Hearing

    Lindsay Lohan attends her probation hearing with attorney Shawn Chapman Holley (not pictured) at the Airport Courthouse on March 29, 2012 in Los Angeles, California. Judge Stephanie Sautner ended Lohan's formal probation after concluding that she has completed the terms of her sentence for her 2007 DUI conviction and probation violations. Lohan is now on informal probation until May 2014 for her 2011 Venice, California jewelry theft conviction. (Photo by Joe Klamer-Pool/Getty Images)

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    Actress Lindsay Lohan attends a probation progress report hearing at Superior Court in Los Angeles, California, March 29, 2012. Los Angeles Superior Court Judge Stephanie Sautner decided to take Lohan off probation from a 2007 drunken driving case. Sautner also decided that Lohan will no longer have to meet with a probation officer or appear in court on her 2011 shoplifting case, as long as she obeys all laws through May 2014. AFP PHOTO / POOL / JOE KLAMAR (Photo credit should read JOE KLAMAR/AFP/Getty Images)

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    Actress Lindsay Lohan attends Domingo Zapata's Oscar Art Show Presented by Mr. C Beverly Hills on February 22, 2012 in Beverly Hills, California. (Getty)

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    Lindsay Lohan leaves the Airport Courthouse after her probation update hearing on February 22, 2012 in Los Angeles, California. Lohan is currently performing 480 hours of community service at the Los Angeles County Coroner's office and attending court ordered psychotherapy sessions stemming from a 2007 drunk-driving conviction and a jewelry theft conviction earlier this year. (Getty)

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  • Ali, Lindsay and Dina Lohan