My African Violet plants get whitish blotches all over.
This sounds like powdery mildew. The solution generally is to paint the areas affected with a paintbrush dipped in alcohol. However, I think I'd clip the blossoms after moving the plants from others near it, and inspect the plants to see if there is any evidence of the powdery mildew on other parts of the plants. It there is, use the alcohol solution to paint the foliage. I hope this helps.