It's hard to tell exactly from the photo, but those look like water droplets which condensed in the lens as it was moved from cold to warm(er) higher more moist conditions.
The moisture can either condense as an overall fog or sometimes (rare) droplets.
Once or twice of the move from cold to warm, without slow controlled warmup, probably does not matter, but if done repeatedly, the film just builds up.
Dust or particles (this is my assessment, see below) get stuck on the inside surface thanks to the moisture - via surface tension.
I don't recall seeing white spots like these before, in my experience, which stretches back over 50+ years, but who knows.
If it is actually a fungus, it is unusual be cause fungus in lenses usually spreads out in a filmy manner over the surface.
As to "Schneideritis" I suppose it is possible, but inside the lens there is nothing white as I recall, it's black as the 'Black Hole of Calcutta" for good reason.
The only harm it can do is perhaps an unwanted reflection off a particle in an image, but it would likely be way too far out of focus to matter.
Unless you are REALLY experienced, this is NOT a DIY project.
Save yourself a LOT of grief, just send it in for service.
