If it looks like someone has dripped a bit of candle wax on them then in my expierience ( carp pox) will clear on its own and is not harmfull.

lost most of mine temp in pond went down to 2 degrees,struggling to get it back up

my mate as lost 95% of his carp his pond is 4ft deep and was frozen for 3 weeks once it started to thaw he found the carp belly up.
some of these fish were 10 yrs old and had been stocked at 6 inch long when they died they were around 3 to 4lb,all the other fish,orfe tench are ok.
just hope that the commercials dont suffer the same fate.

Generally it clears on it’s own, although I have one common in my pond that seems to struggle to shift it and has had a small bit on it’s lip for over a year, albeit smaller than it was. I did keep saying I’d dispatch it but I can’t bring myself to, it’s a struggle to get much of any fish here for reasonable prices now (and the choice is rubbish!) let alone get hold of commons and mirrors!

I’m no expert but it tends to appear in my pond when the fish have been distressed for whatever reason. It could just be the cold temps and hopefully it’ll clear for you but it may be worth checking your water etc, just to make sure.