This started about 13 days ago after my filter on my 20 gal went out

while I was gone for 2 days, it has sense been replaced with two new filters and the tanks chemisty was returned back to normal soon after with a 75% water change.
First we noticed a red patch on the side of the body and then 1 scale fell off. The reddened seemed to grow to a second scale which seemed to rot away and eventually fall off and then again to a third. We treated the water with Tetracycline and ran through the treatment with little to no effect. In fact there seemed to be an increase in the amount of visible veins throughout the fish indicating vascular inflammation. We switched to Jungle Anti-Bacterial Medicated Fish food, ran through 2 bottles over a period of 3 days. The redness has stalled for a bit but now has increased in size within a period of a day and there is a small white raised bump (approx 2mm wide and 2mm raised) on the upper aspect of the ulcer. After much research I am at a total loss of what this could be???
My only guess is Ich and maybe a bacterial infection all hitting at the same time due to the stress? I was thinking maybe a saltbath??? Any suggestions for a disease and treatment? Thanks!
Ulcer, hard to see the bump.
You can see the raised bump looking from the posterior of the fish.
You can make out the bump and the relationship to the ulcer.
You can make out the bump and the relationship to the ulcer.
You can make out the visible veins from the vascular inflammation that popped up.