Why dress for warmth when you can expose yourself? Designers are doling out sheer necklines for fall’s cocktail attire. Proenza Schouler’s iridescent midnight-blue dress comes with see-through ornate collar and bodice. Erin Fetherston’s black minidress covers up (sort of) with a sheer black, three-quartered sleeve overlay. And BCBG’s geometrically cut-out collar and sleeves offer slivers of skin, which will accessorize nicely with goose bumps.