You can and should goto a doctor to be tapered off.
I switched to a good reputable doctor to taper me off of benzos. I told him my xanax dosage, and he lowered that and changes it to XR a few consecutive months then switched to valium. Since I told him the dose I was on, and asked to be lowered, he did not mind doing it since anybody seeking to get high would not do this. I also volunteered my previous docs name if he wanted to double check but he didn't bother asking, im pretty sure there is a database that tracks prescriptions filled anyways that docs can check.
Since you have not gotten them from a doctor before, I would just explain the situation, and explain that you will lower n continue to lower your dosages as they deem fit. I'm pretty sure that my doc knew that after 5 yrs on 3mgs of xanax that I was not getting high off of lower doses of xanax, and then valium when I got down to that so your doctor should not be hesitant if he is lowering the dosages.