Sorry it would not be possible to show the the region next to posts.
The "IpCountryLookup" connects to an API service that we run on a small web server that returns the country code for the IP from a IP database.
The service is provided for free, so there is not allot of resources available, and therefore the API is only used for a very limited number of purposes and not on pages that load often, like pages show posts, to avoid placing too much strain on limited resources that we can allocate to the API service.
You could try adding the functionality yourself as
www.maxmind.com and
www.ip2location.com both offer self hosted databases and APIs that you could use to get the region for the IP address.
Although these database do tend to show the region the ISP is located and not the region where the end users is located, which maybe a different place.