And it turns out that

Just as planned

Opening his eyes, Josh first saw that the bathroom was mostly unchanged. The only addition was a little shelf installed next to the mirror and sink, filled to the brim with cosmetics. On closer look, he realized that the shower had an additional shelf too, filled with soaps and hair products. Curiosity getting him, Josh inspected the labels. Few bottles were for straight, wavy hair while another was for thick, curly hair. In the mirror-cabinet he found four toothbrushes - of which he recognized the blue coloured one as his old one.

Just then someone knocked on the door and Josh nearly jumped out of his skin:
"Honey, is everything all right? You're taking awfully long in there!" An unfamiliar voice asked through the door. 'Wait a minute - I do know that voice'

As soon as Josh put his mind to it, new memories surged forward in his head - memories of a past that had not existed before, that actually was completely new to him. He seemed to remember two different pasts, but the old one, the one before changes, was quickly fading, being replaced by memories of his life in this new world, as if the changes he effected had always been there!