Permit Question - Converted room to bedroom

[Jee Lee]

We recently closed off one doorway in an old dining room but now I'm wondering if we should have pulled a permit to do this? The home was a 3 bedroom and we converted it to a 4 bedroom. We did not mess with anything structural or electrical. The room has two windows with a vent for AC/Heat. Was this supposed to be permitted? 

The issue we are running into is listing this as a 4 bedroom home for rent but don't know how to update county records that it is now a 4 bedroom. Zillow does not allow the listing to be updated to a 4 bedroom. They pointed me to my agent but my agent can't update it for a past sale.