If you are using JetPack with it’s in built sharing tool and you have lost your Facebook likes because you have switched your domain to https, you can now recover the likes by installing Really Simple Social.
Why is social share recovery necessary?
When you switch your site to https / SSL, you are actually changing your domain, as far as Facebook is concerned. So because likes are linked to your domain, they’re zero on your new domain.
The Really Simple Social plugin uses a filter in the mixed content fixer from Really Simple SSL to replace the url Facebook uses back to http://. This way you can regain your likes.
Does it always work?
The native recovery works most of the times. Sometimes Facebook starts returning the https likes whatever you do. And sometimes Facebook returns a different count for www and non www as well. If that happens, you can use the custom share buttons that are built in in the social recovery plugin.