Maybe this is scale? Leaves are glistening and look like they are sweating although dry to the touch. Also white dots cover many leaves. Thanks for your advice.

On my phone it is a bit small. I would say thrips rather than scale. Get a general purpose insecticide for indoor use, and treat as per package instructions.

Wow. That didn't happen overnight.

You're f'd if you don't get on top of it soon. I'd go heavy on the insecticide soap then get a bag or box, put the plant in there and release a bunch of lady bugs in with it.