Dave Bonta's three-line poem is built around a quiet twist on the phrase "self-care." We usually imagine self-care as something you do for yourself, but here the speaker splits into two people: the daytime self who does the caring, and the night self who needs it. All morning, the speaker tends to "the one I am at night."
That night self is never described, which leaves us to guess. Judging by the title and the idea of needing care, it might be someone anxious, sleepless, tired, or haunted by thoughts that only show up in the dark. The morning is spent repairing or soothing whatever that person went through.
The tone is gentle and a little weary, but not hopeless. There's tenderness in the idea of being kind to your own worse hours. The short lines and the break after "the one" make the poem feel like a pause, as if the speaker is quietly noticing a habit they have never said aloud.