So, making large changes like that is something you should get a maintenance window to do. Even if you think it's fast, you want time to check your work. Users handle known outages much better than they do surprise ones, especially on plan-able work such as DHCP scope changes.
Were you using DHCP reservations for your devices? Did you recreate those reservations and validate them?
You may have to take this one on the chin. Sorry, friend.