Breasts not much of a smaller size after breast reduction?

Although there is still some swelling one month after breast reduction I don't think you'll see a sizable decrease in size.

Your surgeon must guide you through your recovery and you must be patient with your results, in a couple of months you will see the real results of your surgery and if you are not pleased you should consult with your surgeon for a revision. Good luck!

While your breast probably will not shrink tremendously after 4 weeks, they can shrink a little bit more as the swelling subsides.  Give it more time.