Left Wrist Remembrance

Greetings, Bilu!
I'm going to get right into this piece.

with many monsters screaming in her bed,

Hm, I think you meant head here? And if you did actually mean bed, you use it again in the next line as well, so that may not be the best choice.

When self loathe overtook her mind,

I think you would have to use "loathing" here instead of loathe. If you want something to be the same number of syllables, then I suggest hate instead.

But never acknowledged the unsaid "but."

I think having the "but" at the beginning of the line takes away from it a little bit. I would use "and" here instead, because it seems to fit in fine.

A soft bubble of blood, a ruby red bead.

I might change this to "a bright ruby bead" to avoid the repetition of red. I think the use of the word ruby is powerful enough, and you already used the word red in the last line.

Thank goodness she always wore a long sleeved shirt,

This sounds a little off, so maybe I would take the "always" out. If not, you could change it to someone like this: "She made sure she always wore her sleeves long/long sleeved shirts". I'm not sure, but it seems to fit a little bit better.

Blame it on a dog or a non-existent cat,

I think you should maybe replace "a dog" with "the dog", because I'm assuming that only the cat doesn't exist, so it's probably her dog. The dog seems to work better for that case.

Who knew she was capable of a lie so fat.

It would really be nice if this line could end with a question mark. Not only is it a question, but you've been using commas and periods to end your lines each stanza thus far. A question mark would be a break at the end, something rather final, like it isn't meant to go on, a rhetorical question.

To finally walk within the light.

This, I thought, was a very interesting way of thinking. I usually think of death (I guess this is leading up to death/kind of focusing on self harm and things?) and harm as falling into the darkness, so it's neat that here it's displayed as light.

This is very moving overall, and you did a good job of setting a dark mood. I wasn't sure at first, but I actually really like the point of view of the scar. It's kind of objective, yet very personal to the narrator as well. Great job with that! This is very sad and emotional, rather like at least one other of your poems, so I hope you haven't had any personal experience with this type of thing. If you haven't, you've done a good job (however horrifying the topic) in conveying the feelings and interactions in here. If you have... Then I am very sorry. I hope you're having a great day!! Nice poem!

-Falconer