Imagine waking up inside another person's body. The speaker says they would handle it with great care, so gently that the person would never know they had been there. It's a tender, slightly playful way of talking about kindness toward someone who may not feel kind toward themselves.
The second stanza widens the focus. The speaker says the poem isn't meant for just one person but for anyone who feels unattractive, and offers a simple reassurance: you are the prettiest to me. The speaker then admits their own flaws, with messy hair and slightly crooked eyes, which makes the comfort feel honest rather than showy. Even if they looked the same, they would still love that body.
The mood is warm, sincere, and gentle. The plea to "love yourself all the time" is the heart of it, and the imagined body swap is just a way of helping the reader see themselves with kinder eyes.