I will answer based on the assumption that taking Percoset for ~6 years is predicated upon medical necessity.
This is a tricky question, but my initial impression based on limited facts provided is that you were not injured above/beyond your pre-existing injury and no medical malpractice resulted.
This may be a professional malpractice case as against your doctor, but even then I am leery of affirming the same without more information.
For medical malpractice to occur, 4 main pillars must be established: doctor owes you a duty; breaches that duty; breach of that duty caused injury; you suffered damages as a result.
I do not know what the 'proper weaning down' of Percoset is, or if it is medically necessary to wean down, at least as is followed in the Brooklyn community. (Standards of medical treatment vary from one area to the next, and lawsuits depend on the standard in the particular community.)
Regardless, once the physician-patient relationship was formed, your doctor owed you a duty to continue treatment and not sever that relationship without proper notice. He certainly did unexpectedly sever that relationship without proper notice, which tangentially resulted in your prescription running out and you experiencing pain. That said, it is unclear whether you suffered any legally cognizable injury.
I strongly suggest you reach out to a local medical malpractice attorney, who, in his discretion, will reach out to appropriate doctors in the community, to determine the extent of deviation your doctor may have strayed from the standard, and if a legally recognized injury resulted.
What is a bigger question to me is that, regardless of whether what your doctor did is proper or not, and assuming the prescription of the med at the dosage you've been taking for as long as you were taking it, was medically warranted and appropriate, why haven't you gone to another medical provider to resume the treatment and thereby reduce or remove the withdrawal affects you are experiencing. The law requires a person to mitigate their damages and if going to another medical provider would do that, then continuing on in pain, etc., will be viewed as being your own fault (culpable conduct).
A roundup of the best tips and legal advice.