The heavy breathing is not always a bad sign with regals. They are quite excitable and just about anything gets them "pumped up". Be sure there is plenty of surface aggitation and check the ph
/ammonia to be safe. Any sign of secondary infection, the eye's are clear?
will embed itself into the fish and can be uncomfortable to say the least. The regal will continue to "scratch" until all the trophonts are gone. As long as the "spots" are not coming back in new locations and the existing ones are disappearing, I would continue as you are. If the spots keep re-appearing, then the treatment is not working.