I'm so sorry Kimmy - this is mirroring exactly what happened to my fish Maddy. There is something you can try, and that's a course of Maracyn I (after the dose of Maracyn II). Usually with dropsy, these are both used (primarily in tandem) as the 2 treat different strains of bacteria (gram negative and gram positive).
I would also see if you can order some metromeds quickly. If you tell goldfishconnection.com you need it urgently, they will express ship it to you.
Do you have a heater you can use? In cases of dropsy (initial stages), people have had success using both Maracyn I and II, raising the temperature to 82degrees and adding 1/8 teaspoon of epsom salt per 5 gallons. Plus, making sure his water is perfect.
I think another important thing here is isolating him to another tank for medicating - your fish that are well wouldn't benefit from all this treatment. Is there anyway you can set up a plastic tub? Have you a spare air stone and small filter?
If you can get some MI - before adding, do a 50% waterchange. MI & II have at times been used together but in this case, you would only have 50% of the MII in your tank so adding the MI won't harm your fish.
This really is a nasty bacteria - the lump first appeared on Maddy then about 6 days later, she started to swell. Without any good meds here, she eventually couldn't fight it off but I do hold out hope for your fish. With medicated food (Ranchugirl has had greater success using metromeds over medigold), raised temp, epsom salt and maracyn - this will give him his best chance