CactiGuide.com

I noticed a few weeks back when I was treating my cactus for mealybugs that my copiapoa marginata was developing white spots on it, I thought it might be spider mites but I have never found any on it but just to be safe I did treat it for them, I was struggling with an outbreak of them on other cactus so I treated everything.

More spots have developed after treating it for both mealybugs and spider mites, and I am unsure what my next step should be?

I'm still pretty new to cactus growing so any advice is greatly appreciated.