The speaker is responding to someone who has asked why they self-harm, and the first thing they admit is that they don't really know. Instead of one clear answer, they offer a handful of "sometimes" statements, each giving a different, partial reason: a wish to feel the pain they have caused others, a way to show people how much they are hurting, a last resort when the inner pain becomes too much, and a way to prove they are alive when their emotions go numb.
The repeated "sometimes" gives the poem a halting, honest rhythm, as if the speaker is searching for words as they go. The final, single-word "Sometimes." leaves the answer unfinished. The mood is raw, quiet, and vulnerable. There is guilt in the line about hurting others, loneliness in the need to be seen, and a deep emptiness in the last reason. The poem doesn't defend the behavior; it simply tries to explain it.