New Mattress And Quilt Cover Set

Hi phoenix, i do have another question but did not want to create another post just for this. My question is as below

I am away on holiday for 3 days. And so I forgot to put a clean cloth over my bed, so basically on top of the bed is just the quilt cover with the quilt inside, and pillow etc, will it get dusty since I did not sleep on it for 3 days ? And if so, what should i do when i get back ? Do i have to wash the sheets again ?

Another question would be, i have looked at the brochure / guide on how to rotate my mattress, what the picture shows is A is head B is tail, so rotate in a way that B will be head and A will be tail, that i am clear, so basically it doesnt matter whether i rotate it starting from left or right , right ? As long as B becomes Head and A becomes tail?