What do you yhink happenes to Kino and Juana after they return to their village and throw the pearl into the ocean?

I think they will be simply left alone. I doubt that anyone will care about them again, considering they have nothing and they are now just another of the oppressed. In reality no one will care about them because they have nothing and they cannot help or hurt anyone. They have made no impression on anyone now that the pearl is gone; they have much to mourn and they will never be the same.