Hi, Christina. I wouldn't use Physan 20 spray on flowers. I think it might do them in, and why take a chance?
Physan spray is a good contact anti-fungal anti-bacterial for the green part of the plant only, or on the roots when repotting, so you're smart to keep a spray bottle of it around. But hold back on the flowers
I don't know what the source of the tiny round spots on a few petals, but they sound harmless to me. Could just be the flower equivalent of a mole-- a concentration of pigment, a small imperfection in the flower.
If you are misting the flowers, don't do it any more. That sometimes will cause grey blights on the flowers.