Mary Astor looks awful! The reason? - SPOILERS maybe
That hair style and make-up. Atrocious! And later in the film, her son takes her to task for the blouse she is wearing.
Without having to sit through this film again, I think the reason for her declasse look is b/c she and her family are supposed to be from the poorer part of town and with little money or breeding. So she wears a shoddy hair-do and wears a thrift store blouse to a fancy party.
I guess...b/c there is no other reason that she should look so ragged.