Cupramine is ionic copper, and is more toxic to both fish and parasites, so it is used at a lower dose. It should still be dosed at 0.50 ppm for 30 days, 21 days at the very least.
If these lesions showed up while the fish was in full Cupramine, you can rule out ich or velvet. Brooklynella would have affected the clownfish. That leaves flukes as a possibility.
Do you happen to have a microscope? Doing a skin scrape is one way to confirm flukes.
Another way is to give the fish a 5 minute freshwater dip. Then, using a magnifying glass, look for flukes in the dip water.
If these lesions showed up while the fish was in full Cupramine, you can rule out ich or velvet. Brooklynella would have affected the clownfish. That leaves flukes as a possibility.
Do you happen to have a microscope? Doing a skin scrape is one way to confirm flukes.
Another way is to give the fish a 5 minute freshwater dip. Then, using a magnifying glass, look for flukes in the dip water.
