A: OK, it took me a sec to figure out what you are talking about, but if this is in re: the fin de siècle fashion of wearing a decorative black patch of paper or fabric on your face to cover up a zit, mole, or syphilitic chancre, there is currently (2018) no law against it, except if the patch covers your entire face and you're in a bank or government building, or if the patch would be of dubious legality regardless of its location (like if the patch was made of a controlled substance). There is, as you say, no less of a sin in wearing a small piece of black paper in the shape of (for instance) a bat than there is in wearing (for instance) a Brooks Brothers suit. But I must point out that sin and legality are very different beasts-- pride, greed, lust, envy, gluttony, wrath, and sloth, those are the seven deadly sins and none of these are illegal. One could make the argument that some of these are even enshrined into law! But about the patch thing anyway you're fine. But as for 1890s England, was it even ever illegal or was that something that people said to keep their daughters from doing it? Any way you slice it, then and now it looks cool, and the haters can (pardon my French) suck it. A parent or guardian might say "why cover up your beautiful face?" but you know what? it's your face. If you want to innovate you have to be prepared to look foolish, and kids especially should practice looking stupid and having older people not understand them, that's a valuable lesson (that confidence carries as well as looks and if you want to get anywhere interesting you're going to spend some time being not understood). Don't: hide. Do: follow your idiot heart.
No one really does the black patch anymore but when I was in high school (Doherty, mid 1990s) there was a brief fad, inspired I think simultaneously by TLC and by pro basketball players wearing Breathe-Rite nose strips, to wear a colorful band-aid on your face. That's basically the same riff. If I recall correctly the administration tried to outlaw it, but how can you outlaw a band-aid? It's a medical device! Of course nowadays you still see this style sometimes but it's more of a club look, and instead of band-aids it's stickers, and the stickers are commonly gemlike, holographic, pearlescent, or all three, befitting the denizens of the future (us). It's cool.
Looking even further into even more future, I would say that there's a good reason to bring back the strictly black/white patch style, which is to use it in the service of countershading to try and induce failure in face-detection algorithms. Also it's a great look.
TL;DR: It's still legal to look cool and it's still cool to be free.