Consult a Plastic surgeon or a Dermatologist.
I had one myself. I was given corticosteroid injections into the site, which reduced the size and then my Derm. lasered the rest away. That was 17 years ago and it never came back, though they can return.
If you have a piece of metal in there you can't (per protocol) have an MRI, which you may eventually need, so it's best to have it removed.
As for removing the kelloid you need a consult with a plastic surgeon.