See https://www.eatortoss.com/how-to-tell-if-white-stuff-on-chee..., https://www.eatortoss.com/aged-cheddar-with-a-crusty-white-s....
The rule of thumb I've heard is hard white: crystal. Soft white: mold.
If you can't tell, I would dump it.
Now, that doesn't mean rando-mold doesn't ruin the cheese's flavor...
Sadly, the wayback machine has snapshots of the article going back to 2020, but doesn't seem to have archived those broken image links.