TW: SH

almost every song on Xiu Xiu's Fabulous Muscles

it's an autobiographical concept album about being a survivor of incestuous abuse 

The Fall of Troy - I just got this symphony goin

It talks about a couple doing a suicide pact, I guess it counts.

cemetery drive by mcr has a brief mention about slitting wrists ig..

Sushi Soucy's I Deserve to Bleed talks about self-loathing and the desire to injure your own body. Dogmatica by Femtanyl definitely has quite a bit of lyrics regarding self-harm (song is VERY loud btw)

While All I Want is You + I'm So Crazy for Youuu from Rebzyyx both focus on self-destructive behaviors (and obsession), both songs really only have, like, one line about self-harm (and it's more so implied, tbh). A bit surprising, considering Rebzyyx's usual themes, but I haven't listened to all of his music so maybe he does indeed have a song about self-harm idk

If you wanna go down the vocaloid route, a lot of Kairiki Bear's songs are all about depression and/or suicide. I think Failure Girl has lines mentioning self-harm, but I can't really think of any others that explicitly talk about it :o

I don't know what type of music you like, but those are my recommendations!