"Bandages" is about a crush that isn't returned. The speaker is sitting around waiting for a reply from a boy, and she's frustrated enough to call him "stupid dumb," yet she's also writing a rhyme just for him. That mix of annoyance and affection is the heart of the poem.
The opening line is the most interesting. She wishes she could fall off her bike "one more time," which suggests she misses a simpler kind of hurt, one that scrapes your knee and heals with a bandage. Heartache is harder to fix. She can't even name what he makes her feel ("i don't know what that thing is"), which gives the poem a raw, honest quality. She imagines singing his favorite songs and being his favorite girl, but the last line brings her back to reality: he ignores her all the time. The mood is wistful, a little embarrassed, and quietly sad. The plain wording and loose rhymes make it feel like a private note that was never meant to be polished.