Leave it. Let the yeast do what they do best. Make alcohol. I would put it back at the 52^ and leave it until they are done. May take a while.
I just did a pilsner. In the primary for 4 weeks at 50^F. The bubble rate wasn't much, but I could see a layer of foam on top so I knew it was still going. When the foam was pretty much gone I racked to the secondary.