"I was really inspired when I heard a story about a little girl who said she couldn't be a princess because she didn't have long hair, and I wanted her, and others like her to know that's not what makes a princess, or a warrior, or a superhero," the Australian actress, 31, wrote in a post on Facebook.
"It's not what makes you beautiful either. It's your insides that count... even if you happen to be missing half of them."
In the post, Bowen wrote that she was diagnosed with end-stage nephroblastoma
when she was 4 years old and became part of a tight-knit group of sick children who were "mostly bald, all tubed, taped, bandaged up and stitched back together."
But they didn't see those things in each other.
"No one got laughed at or teased. We were all we knew," she wrote.
Bowen got well, and her hair grew back.
"I look relatively normal on the outside, but on the inside, I am still the same stitched back together little creature, in a world where people are judged so harshly for the way they look," she wrote.
"Every scar tells a story, every bald head, every dark circle, every prosthetic limb, and every reflection in a mirror that you might not recognize anymore."
She encouraged fans to look beyond appearances.
"You are who you are in your bones. That is where you have the potential to shine the brightest from. It is where your true beautiful self lives."
Bowen thanked the network, the series creator and her friends and family for supporting the decision to change her look.