Well....I went in and started yanking.
I think you are right that this is going to require a complete redo.
Here are a couple things I learned.
* If you are are very careful, you can remove strands from the carpet with tweezers. Dig around with the tweezers and locate 1-2 strands. grab, and instead of pulling up, pull to the side. That way you can remove a small number of strands, without pulling up the entire carpet.
But....pulling up and replanting seems to be the answer here.