Shin bang is a very real and painful thing and much will depend on the brand of the boot and as well as the padding, how, depending on the shape of your leg the boot conforms to you. Each boot is a bit different though the usual complaints are in the toe box (toe bang that leaves you with black infected toe nails) or heel lift that is critical and perhaps the most important part of how the boot will affect your skiing. It's like a steering linkage in the drive line of your car, any flop or loose area and the "Porsche" is all over the track.
Going to a professional boot fiitter is probably the answer. But they may not be able to make adjustments to the boots you bought. Often they have used boots that may be better so be open to that since they get folks like myself in there who after years of pain (run over as a kid), I'd trade my first born to ski pain free. Greg Hoffman did more than that, kept my boots and the adjustment left me pain free and the balance was outstanding. I was a new me after 40+ years on skis.
This has to be said. There is also a chance that you are skiing more and I noted your comment that you have been risking some black runs. This also tells me that you are probably sitting back (a natural reaction when you fear steeper terrain. Is the pain more intense if you are staying on the easier greens that are well groomed. Crud and moguls are tough on all of us because the sudden braking effect in junk snow will pitch you forward of course. Now, keep in mind that in a boot that fits very well and is snug there isn't the room for the movement and crash bang.
Martial Arts and skiing? Yeah, there is something in common and be it knuckles or any other contact surface we "harden" by developing callouses or in the case of shins, (not to the extreme like Thai boxing) you eventually, through contact will deaden the nerves.
My shins would hurt like the blazes for the first week or two back in the boots after a lazy summer. Once I realized it, and I don't expect you to do this, I would start to spend time kicking the heavy bag with my shins a few weeks before the season started. Instructors don't aside from usually having a good fit, have any magic aside from having deadened most of the tender spots.
One of my initial thoughts would be to get your doc to prescribe a thin Lidoderm patch but that would probably just bunch, tear and blister being a bigger problem.