Sarah's poem is only a few lines long, but it makes a sharp turn in the middle. It begins with a surprising claim: being in pain is beautiful. Pain here seems to carry a kind of honesty or depth, something that can be admired. Then the poem complicates that idea. Once you are beautiful and in pain, it says, the situation becomes "a death sentence."
The speaker seems to be thinking about what happens when suffering is turned into something pleasing to look at. If your pain looks beautiful, people may admire it instead of helping, and you may be trapped in a role where hurting is expected of you. The poem doesn't say this outright, so that reading is an inference, but the harsh phrase "death sentence" suggests the speaker feels something close to doom.
The mood is bleak, quiet, and controlled. The short lines and the comma that pauses before the last line make the ending land like a verdict.