Bubba's still sick.

[Drift]

Sorry if I seem impatient I had posted on Monday, but he is my oldest guy and I don't want him to die because I neglected to do my best to find out what is wrong.
So I posted previously about the small white sore on his face. It's between his eye and gills. It had looked like puss was coming out before. Like when you pop a zit and if you left it there. A thick white kind of substance.
He hasn't had any medications for a full week now. It look like a small white sore on his face. Some of his scales are gray and loosing color and he has started to do this thing where he will bend to the right like he's trying to itch it.
He had been lethargic, placed heater and he's been a bit more active. I believe he is a bit depressed/bored and misses his 10 gallon that's under going planting and cycling. He's very spoiled. :) He does have one plant his floating log, and his barrels he likes to hide in. Oh and a floating mirror he's in love with. He made a bubble nests around it when he was feeling good.
I did a treatment of Lifeguard (5 days), Tetracycline (4 doses) and fed him Jungle Anti-Bacterial Pellets for 5 days, and Jungle's Fungal tabs. Please note this started around the first day of July or so.
He's in a 2.5 gallon unfiltered tank. Doing 100% water changes every 4 days. I was feeding Hikari Bio Gold, but switched to Omega One. Just bought Hikari frozen blood worms today. Will start feeding him them tonight. He has a heater in tank maintains a lovely 80degrees. I use an in tank thermometer.
I've had him for 2-2.5 years and he was bought at the pet store. So I'm guessing he is 3 years old if not older. I know he's on the older side but I had one for 9 years live in a 1 gallon with once weekly water change and minimal care.
I used aquarium salt with every water change and API's Stress coat.
Yesterday's water change I did not add any salt. Was 100% change. I'm letting him sit in some nice happy clean warm water while I wait for someone's opinion.
I think I had been under feeding all of my betta's and they're all on the skinnier side but should resolve with the higher quality new food. Someone had told me to only feed 2 pellets 1x a day. :( My one kept getting bloated but now I understand it was food quality.
He's had a history of Hole in the Head disease fixed with more frequent water changes when he was in a one gallon 2.5 years ago. Fin rot, used Jungle's fungal tabs, Columnaris treated with Tetracycline and Anti-bacterial pellets, and he had fin rot this past early June and treated with the Tetracycline as it was labeled for that too. So possible built up resistance to the Tetracycline. I have Triple Sulfa on hand, but wanted to see what everyone else says first.
I do not think this is Ich or Lymphocystis.

Sorry for the long post, I just wanted to put as much info as possible.
I'm hoping I can get some opinions or possible diagnosis.
If no one here can help and he's still alive in two weeks is the Keystone Veterinary Conference and there are several fish veterinarian/experts I will consult with.
I really love this fish and I've spent close to $1,000 on his 2.5 years of living with me from upgrading tanks, routine care, medications, heaters clunking out. So anything your throw at me I'm willing to spend money on, even though I barely make more than minimum wage.

[Drift]

I was able to get some ok pictures. This is the best one. You can see the white sore with puss/fuzz coming out. But also the kind of loss in color on scales and fuzzy-ness on head. In crease in heat seems to have made it worse!
My poor boy is super itchy.