Tough to see, but at one point, I did see what looks like Neobenedenia flukes. In the previous pictures, the foxface looks like it has ich. Hyposalinity, if you can do that, will treat both of these issues at the same time:
Hyposalinity Jay Hemdal 2024 This term refers to a long-term bath treatment for marine fishes in which the salt content of the water is lowered and held below the point that certain parasites can survive. The salt level reached, and the time of the treatment are the two variables...
www.reef2reef.com
Jay