Hi,
It depends entirely on what was causing the symptoms. Not all RI's have the same underlying pathogen.
I would try giving him a soak in 86f water no deeper than half way up his side for 30 minutes and then, if his tongue is still stuck together the next day tell the vet and see if he feels another course of the antibiotic will be needed.
But keep your quarantine going until all the symptoms have gone and, ideally, for a few weeks afterwards just to be sure.
Caution is by far the best policy.
dr del