Disagree with @jessica681 here. A quick thank you seems too casual for such a big deal. If a group like BLACKPINK shares your work, you earned a moment to say more. Explain how it felt or what inspired the sketch. It makes the moment real, not just another comment. Keeping it brief might come off as not caring much, honestly.

Seriously, @the_faith has a point about rushing hurting quality. But you can have both speed and a good job. My trick is to pre-stage my kit the night before a big day. I lay everything out, check all my adhesives are fresh, and make sure my portable forge is clean. That way in the morning, I'm not rushing, I'm just grabbing and going. It's the prep work that saves time, not skipping steps.