The normal "Edit in Photoshop" method should have automatically imported the newly saved image, into Lightroom, without needing to Sync the folder.

However, this does not necessarily mean that this new image will immediately show in the same Collection, Smart collection, filmstrip view or grid view as the starting image does; or even if it does, it may not appear next to the starting image.

That is all merely a question, of how exactly you are viewing the image library at this given moment, and of what attributes and properties the various image versions have, which are relevant to that. The original and the edited versions filter, select, sort, have membership in Collections, etc independently.

Also these two may (and will by default) be involved in a stack - so one or the other gets sometimes concealed from view due to that.

Ian Lyons wrote:

For the Photoshop edited version to be placed automtically back into a collection the user must first have sent the original to Photoshop from within that collection. Sending it to Photoshop from within a folder means that edited version it will not be placed into a collection, irrespective of whether the original was in one or not.

I wasn't aware of that extra subtlety - thanks. I suppose it's logical enough once you know about it .

So perhaps the OP might have used Edit In..  from a folder based view in this case, and from a collection based view on earlier occasions?

Something else that might be helpfully. There is a preference in photoshop that toggles all "save as" files to be saved to the parent file. Otherwise it goes to the last used location be default. In my workflow, all the "edit in photoshop" files sow up in the catalogue, but any "save as" versions need the synchronizing click to show up.