Lohan contracted chikungunya, a rare incurable virus that causes fever, joint pain and fatigue, while vacationing in Bora Bora over the holidays.
She posted Instagram photos from her trip, seemingly in good spirits despite her illness.
"In good faith with good people." Lohan wrote. "I refuse to let a virus effect [sic] my peaceful vacation."
Lohan also thanked Oprah for her concerned call in another Instagram photo.
Lohan returned to Los Angeles after her vacation, reportedly to shoot her Esurance Super Bowl commercial, before traveling to London, where she was hospitalized with a high fever and joint pain.
Sources say Lohan has since been released from hospital care, but her joint pain could last up to several months.