Okay. Here's the update. I still haven't gotten my meds yet in the mail (

), but I have already gone ahead and set up a clinical tank for my oscar to be treated in. It's 3 gallons, I've made the water 0.2% salinity for a nice salt bath, and I've added a long air stone for for the best aeration.
I moved him from the Angel tank. The Angel tank was more acidic so I'm going to gradually (0.1 / day) raise the pH to a comfortable 7.2 with sodium bicarbonate. I've been slowly raising the temperature as well, trying to get him to eat, but, as far as I'm aware of, he hasn't yet.
He has been hiding a lot underneath a large piece of driftwood that I have in the other tank. I thought this private get-away would make him more comfortable. He seems to be doing fine in his new quarters, however, I've noticed some discoloration on his scales. His color has weakened a lot since this began, but now, under some light, a brown streak is apparent on his spine just below the dorsal fin. Maybe it's just the lighting.
I'd love to post pictures, but it's difficult with the poor lighting, and I don't want to use a flash since he's probably stressed out enough as it is. I've also noticed what appears to be the true beginning of Hole-in-the-head disease. There is this white spec thing somewhat protruding (very, very small at the moment) out of his head on the left side. I'm assuming it's the workings of an epithelial leisure, but I cannot be certain.
Any additional comments, advice, or dis-advice would be greatly appreciated.
I can't wait until those meds get here!