Shannen Doherty has unveiled scary new details about her battle against breast cancer.

The 45-year-old, who was diagnosed with the disease in February 2015, revealed that her cancer may have spread in a new interview with "Entertainment Tonight."

"I had breast cancer that spread to the lymph nodes, and from one of my surgeries we discovered that some of the cancer cells might have actually gone out of the lymph nodes," she said. "So for that reason, we are doing chemo, and then after chemo, I'll do radiation."

The former "Beverly Hills, 90210" star also revealed she underwent a single mastectomy in May. While she is doing everything within her power to fight the illness, she admits certain worries nag her.

"The unknown is always the scariest part," she admitted. "Is the chemo going to work? Is the radiation going to work?" she continued. "Everything else is manageable. Pain is manageable, you know, living without a breast is manageable. It's the worry of your future and how your future is going to affect the people that you love."

Doherty praised her loved ones, who have become a crucial support system during her health scare. She recalled how husband Kurt Iswarienko was always at her side during post-chemo treatments.

"I am in bed and it is a rush to the bathroom," said. "It's, you know, you're throwing up every single second. After my first treatment I lost 10 pounds, instantly. You're throwing up and the last thing you want to do is be in a car. You don't want to be moved, you can't eat. But my husband has to, you know, pick me up. He puts me in the car, he buckles me in, and he drives me to my oncologist and they hook me up to an IV and I get hydrated...There's nothing going in my body, it's all going out."

A photo posted by ShannenDoherty (@theshando) on

Likewise, Doherty's mother Rosa Doherty has stood alongside her daughter every step of the way during her illness. When the star decided to shave her head and document the process via Instagram, her mother was there to assist her.

"It was just shedding and it was driving me crazy," Doherty said of her post-chemo hair loss. "It was just clumps, and I was like, 'Just grab the kitchen scissors.' And my mom's like, 'Wait, wait, wait.' I'm just, like, 'Grab it.' She went and grabbed the kitchen scissors, and put it in a ponytail and she just chopped it off. And it was this cute little bob, but it wasn't enough, you know, it was falling out."

Though her decision to post shots of her shaving her head were in part fueled by her desire to control how the manner in which her new look was presented to the public, she also did it in a show of solidarity with other individuals suffering from cancer.

"I wanted to put it out there the way it felt the best for me to put it out there," she said. "And also, if I could help one person then it makes me go, 'Oh OK.' It's easier to live with having cancer if I know I'm helping at least one person."