"In doctor's office lighting, I didn't tell you I was scared," sings Swift in the new song. "That was the first time we were there, holding orange bottles too/Desperate people find faith, so now I pray to Jesus, too."
The song's chorus echoes the title, "Soon you'll get better," a message to her mom.
In a live stream on Thursday, Swift told her fans that the song was difficult for her to perform, though did not elaborate why.
"We as a family decided to put this on the album," Swift said during the live stream. "It’s something I’m so proud of. I can’t sing it, it’s hard, emotionally, to deal with that song."
"It's taught me that there are real problems and then there's everything else," Swift wrote in Elle. "My mom's cancer is a real problem. I used to be so anxious about daily ups and downs. I give all of my worry, stress, and prayers to real problems now."
In the September issue of Vogue, Swift explained that the relapse was "something that my family is going through."
In the song, Swift shares the way her mother's illness is impacting her life.
"I hate to make this all about me/But who am I supposed to talk to?/What am I supposed to do, if there's no you?" Swift sings.
With "Soon You'll Get Better," Swift may have given us the most in-depth look we have into her family life yet.