If it's only one size too small you might try a longer stem, maybe a different handlebar to suit your preferences for reach and drop.

I see a lot of pros and wannabes locally riding frames that are technically too small, but they want the exaggerated drop from saddle to handlebar. So they use longer stems to set the reach appropriately.

No way I my neck could handle that kind of drop so I have no idea how that setup affects handling or whether a too-small frame might still have problems that could affect the knees, hips, etc. Might also be appropriate to change crank lengths.

I still prefer the old school fit -- more stretched out, maybe 2" or, at most, 3" drop from saddle to handlebar.