First, it is normally requested the actual numbers for the ammonia, nitrite, pH, KH, temperature, not a statement that the water is normal. Normal doesn't tell us anything, and if the actual numbers indicate a need for some changes to the water, they are cheaper to fix than the cost of treating the fish.
From the picture, there doesn't appear to be any infection on the cut, so for now no treatment would be the best treatment. Good water quality is imperative for healing. You mentioned flashing and isolation, which would indicate a high probability of parasites, but could also indicate water quality issues. Your treatment with the Proform C and Prazi should take care of the parasites, but if the fish haven't responded, or don't soon, then your treatment protocol was not what was needed.
Please furnish us the numbers.
Zone 7 A/B
Keep your words sweet. You never know when you may have to eat them.
Richard