What do I do to get restitution from a doctor whose treatment made me severely ill?

You should obtain the opinion of the liver specialist as to the cause of your liver failure.  If the liver specialist's opinion is that the pills from the first doctor caused your liver failure, then you would have a case for medical malpractice.  Medical malpractice is negligence which is the failure to exercise due care (that degree of care in this case that a reasonable physician in the same community would have exercised under the same or similar circumstances).

If the liver specialist's opinion is that the cause of your liver failure was the pills from the first doctor, you want to obtain your medical bills, medical reports and documentation of wage loss.  Compensation for the medical bills is straight reimbursement.  Compensation for wage loss is straight reimbursement.  The medical reports will document the nature and extent of your injuries and will determinet the amount of compensation you receive for pain and suffering.  Compensation for pain and suffering is an amount in addition to the medical bills. 

Prior to filing a lawsuit against the doctor, it may be possible to settle the case with the doctor's insurance carrier.  The claim you file with the doctor's insurance carrier will consist of the medical bills, medical reports (the medical report from the liver specialist is of critical importance) and documentation of wage loss.  If you are dissatisfied with settlement offers from the insurance carrier, reject the settlement offers and file your lawsuit for negligence against the doctor.  You will need to file your lawsuit prior to the expiration of the applicable statute of limitations or you will lose your rights forever in the matter.  If the case is settled with the insurance company, no lawsuit is filed, but if it is not settled and the statute of limitations is approaching, file your lawsuit prior to the expiration of the statute of limitations or you will lose your rights forever in the matter.