Yes!
But what are we talking about? Is your life about outward appearance only, meaning, does everything revolve around your looks?
I’m poor but I love certain products and would rather go without than buy just something of the rack, is that vanity? Yes! But I would not go hungry because I can’t afford to eat at a restaurant–get it?
Taking care of ourselves (clearing acne, exercising, etc.) is a superficial thing (vanity) but as long as we don’t become immersed in such triviality or pass judgment on others because of their inability to enjoy the same or place others above the rest because of their “good” looks… it’s business as usual.
Now, if you pass out because you are dieting yourself to death or killing yourself over exercising in order to fit “xyz” mold… well, you are not loving yourself (which is part of the Golden Rule) so that would be sinful!
Maran atha!
Angel