I think his sore bits might be sore for a couple of days, and take a couple of weeks to heal up nicely. A bit like how long does it take a bruise to go away.
For the sore throat - a (half a) teaspoon of honey might be good. Let Nelson lick it off the spoon. It's soothing and it has some antibacterial qualities to help prevent throat infection of the bits that got damaged/irritated by the tubes. And yoghurt - a desert spoon or so of plain yoghurt per day might also be good - also helps if he's been given a dose of antibiotics to prevent his ex-nads wound from getting infected. And I'd feed soft food (eg tinned or home made casserole) for the first few days.
And if he starts chewing or licking the spot - you could apply aloe vera juice to the outside. Tastes horrible and is really good for scar prevention / minimisation. Large doses of aloe vera aren't good for dog but very unlikely he will want to eat lots of it.