I heard of the semi colon tattoo a few years back. I liked the idea. I never got it simply because it didn't fit into the designs I already chose.

They are other common tattoos for mental health. Blackbirds come from the song Blackbird: "take these broken wings and learn to fly". Butterflies have always symbolized change/metamorphosis. There's something called the Butterfly Project and instead of drawing, many people choose to tattoo the butterfly.
The Rules:
1. when you feel like you want to cut, take a marker or pen and draw a butterfly wherever the self-harm occurs.
2. name the butterfly after a loved one, or someone that really wants you to get better.
3. NO scrubbing the butterfly off.
4. if you cut before the butterfly is gone, it dies. if you don't cut, it lives.
5. another person may draw them on you. these butterflies are extra special. take good care of them.
6. even if you don’t cut, feel free to draw a butterfly anyways, to show your support.

I, myself have a blackbird tattoo and butterfly tattoos. I also have an orange ribbon corset for self-injury awareness. I did these not just for the design nor to cover up the scars, but to help stop SI. My Pdoc said she has other clients who tattooed for the same reason and it works for them. The awesome thing is that I get people stopping me all the time to comment on my tattoos. Most of the time I explain to them the meaning behind the tattoos and they seem to be pretty accepting...even when I tell them about the SI.

I think if someone wants this tattoo, they should go for it even if it's only a fad.

Btw, the wrist is the most common place for the semi colon tattoo, but it's not the only place people tattoo it. And many tattoo the semi colon and an infinity symbol below it.