Have you ever had a pair of binoculars that you turned around and looked through the large lens to the small then whatever was the scene beyond. That is all there is to the small universe that might exist within the large. You would be talking relative difference from here to there, not real difference this end and that end. That end would have this end the small universe within the large universe. An 'Alice In Wonderland' / 'Through The Looking Glass' kind of micro-macro / macro-micro kind of reversal of look and physics. The other end of a wormhole, maybe. A whole lot (infinities) of wormholes to a whole lot (infinities) of universes, maybe. A specie of Multiverse multi-dimensionality.