I would do as
@Eggcessive has described first. See if the swelling comes down, and if it starts to look better. As swollen as it is, I would do the soaks, topical treatments and the oral antibiotics. I have had very good results with sugardine on some bad bumblefoot cases, but it may be hard to get it to stay on that foot since the swelling is kind of all over. I would try the ointment first, be liberal with it and work it into any openings in the skin. Reapply as needed. Give it a few days of that, if possible, and see how things are looking. If it starts looking much worse, then you can reassess. I would not be surprised if a lot of that crusty stuff on the bottom comes off with repeated soakings and cleanings, I wouldn't force it, but if it comes off then that is probably a good thing.