well, i haven't had a habbit like this but um...
what i do when i had a habbit of bitting my nails is imagine that there are little bacteria babies and bacteria homes on my nails and by biting them i am hurting the little bacteria babies.

idk it worked for me

sorry if this doesn't help

idk if this would help a habit of 6 years but... when i wanna do something like this sometimes i take out a marker and just doodle on my arm, its distracting

idk anything about habits sorry
but i wonder if getting another habit that's less dangerous could distract u

Get a fidget toy to carry around !!
Whenever ya catch yaself doing
The bad habit, fidle with the toy!

I would say take a marker, and anytime you want to make a mark, use the marker instead. That way, you can physically see the damage you avoided, while still making an action. Eventually, you could move away from the habit, but you've gotta start small. You can't quit cold turkey.

If that doesn't seem to work, try Google-ing some healthy alternatives that you could try.

I believe in you, Addison! You can break this!!

You could try aversive conditioning. Like wear a rubber band on your wrist and snap it on yourself when you catch yourself picking at your skin. Eventually the pain will be associated with the bad habit and you'll stop bc of the pain.
Or something like that.
The marker thing sounds good, but it may work better for conscious habits. Idk if your skin picking thing is a subconscious habit or not so I'd try both?
I wish you the best of luck!