We found out quite bit of information in her interview published in the October 2016 issue of The New York Times.
While she was at the clinic, she became desperate to write music. Her boyfriend found a toy keyboard for her, and after some negotiation, the staff let her keep it. She wrote songs and she did therapy and she received letters from fans. She did therapeutic coloring, and one day she began writing letters back to those fans on coloring-book pages, writing around pictures of dinosaurs and kittens playing with yarn, “Someone I work with has literally driven me into this disease, tortured me and [expletive] with me and my family,” she wrote in a letter that was posted to social media. “So I’m here taking time and getting my magic back dammit.” This was the first time the public had heard these claims.
She left treatment in March after two months. The first thing she did was remove the dollar sign from her name. “I’m just fun,” she repeated, this time in a sour voice. “That’s all I am. That’s it. ‘That’s all you are. That’s all you are.’ ” She leaned toward me. “I was taking back my strength, and I was taking back my voice, and taking back my power, taking back my body. I’m just taking back my [expletive] life.”
The second thing she did was file her lawsuit.
Here are the pictures we have of Kesha while she was in rehab.