Hi BettaMomma 
I'm sorry to hear that he has not improved overnight.
It sounds like the bacterial infection has taken over. Keeping him in a high temperature will promote bacterial growth and it seems like this has happened.
There is only one last thing to try at this advanced stage. It might seem harsh, but it might save him if it works. Unfortunately, he will probably never be the beauty he once was, but if you are like me, that will not really matter.
I would gradually drop the temperature to no higher than 95 96 degrees. Then clean his tank and add MelaFix. Give him salt baths to clean up the bacterial infections on his skin. We can only hope that the tetracycline is working on him on the inside.
To prepare the salt baths, dissolve one tsp. salt per 2 cups of clean dechlorinated water. Put him in and leave him for up to 20 minutes to 1/2 hour. If he rolls over, terminate the treatment and return him to his tank. Repeat this as often as you can, up to 6 times a day. Prepare fresh solution each time.
The concentrated salt solution will literally eat away the infection, much like when you pour peroxide on a wound. The MelaFix will slow it's regrowth between treatments. If he still has ich, this will help that too.
I have saved corys that I bought with bad infections, that did not respond to antibiotics, by doing this treatment. It's an old fashioned remedy and while it might seem harsh, it's worth trying if it can save his life.
I'm sorry to hear that he has not improved overnight.
It sounds like the bacterial infection has taken over. Keeping him in a high temperature will promote bacterial growth and it seems like this has happened.
There is only one last thing to try at this advanced stage. It might seem harsh, but it might save him if it works. Unfortunately, he will probably never be the beauty he once was, but if you are like me, that will not really matter.
I would gradually drop the temperature to no higher than 95 96 degrees. Then clean his tank and add MelaFix. Give him salt baths to clean up the bacterial infections on his skin. We can only hope that the tetracycline is working on him on the inside.
To prepare the salt baths, dissolve one tsp. salt per 2 cups of clean dechlorinated water. Put him in and leave him for up to 20 minutes to 1/2 hour. If he rolls over, terminate the treatment and return him to his tank. Repeat this as often as you can, up to 6 times a day. Prepare fresh solution each time.
The concentrated salt solution will literally eat away the infection, much like when you pour peroxide on a wound. The MelaFix will slow it's regrowth between treatments. If he still has ich, this will help that too.
I have saved corys that I bought with bad infections, that did not respond to antibiotics, by doing this treatment. It's an old fashioned remedy and while it might seem harsh, it's worth trying if it can save his life.
Wouldn't he cook in those temps?? I'll leave it at 82 for now - then wait for your response...
I also struggle about how many meds to add. I just figured out today that there's a base level of ammonia! in my tap water, my fish have ich and now I think they have internal parasites, too. 
