It seems to be a poem, therefore I think we should keep the lines the way they are in the original.
Would you edit mantaining the length of the lines, please?
Sure, she did a great job!
However when translating poetry we have to make an effort in order to create a poem in the target language as well. Sometimes we need to change the original words to get some rhyme (if the original has it).
It's quite difficult getting a good translation from a word-by-word work.
What is important is keeping the meaning.
I don't think this translation would be "harmed" if we try to make it look like a poem.
My suggestion:
I'm watching over you,
nobody else will touch you
On the palm of my hand
You're my engraved secret
I'm watching over you,
wherever I go you are
On the palm of my hand
You're my lifeline.