I always clip a teaser. lol. I can't help it, and nor do I feel bad about it. Growing is a game of patience, and sometimes clipping one or 2 of the smaller buds early will help you to not harvest the whole plant early just because you want to smoke it.
As for the issue at hand, I don't think correcting it will effect your harvest too much at this point. But for future reference, zinc deficiencies are typically caused by too much phosphorus. Zinc is a micro nutrient, required in very low quantities by the plant, but phosphorus locks out zinc. In order to induce a zinc deficiency in any plant I'm pretty sure you would have to have a special nutrient formula with 0% zinc.
It could be possible that it's just too close to the light too. Would explain why the parts of the leaf covered in trichs is still alive, while the part not protected from the light is necrotic.