Your cat’s grimace is actually sweeping the scent into the roof of her mouth so that she can smell and taste the it. You’ll often see this response if you’re wearing a different perfume or shampoo, or if she happens upon something on the floor that catches her attention.
There are some scents cats find offensive, they usually dislike citrus or spicy smells. Be wary of deodorized litters, too, as the scent may irritate the cat and cause her not to use her litter box. The strong chemical smell in cleaning products can be an irritant too.
Notice that your cat isn’t spending much time with you since you bought that citrus-y cologne to wear this summer? She’s just letting you know she’d prefer you switch to another scent, catnip perhaps?