Bleeding and peeling after in-office Zoom Teeth Whitening? Is this normal?

I went to a dentist for a Zoom! Teeth Whitening session yesterday. No gum protection (other than gauze) was placed, and immediately afterwards my gums were white. The color returned overnight, but now they're painful, bleeding, and peeling. How worried should I be? I just got my braces off and I did a lot of research before I went; I looked into the prep, procedure, what to expect afterwards, etc. This definitely didn't happen in any of the cases I saw. Please advise.

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