small white dots on my rainbow?

Please don't interpret my statement as "they're normal" - they are still indicative of a problem. It's just that this is an early warning in high humidity environments.
Too much moisture is a common cause; though it can be as simple as the snake pressing up against something for an extended time (esp with water, or moist substrate involved). I had an amazon tree boa develop blisters after he chose to use his water bowl as a hide. He seemed comfy, so I just put another bowl in with fresh water. (The first bowl was mostly empty, it had gotten spilled during feeding; and he went in after). When I finally forced him out of it, he had a bunch of blisters along one side. Basically, some substrate had gotten pressed between him and the side, which caused the ulcerations. It was ugly, but he was good as new after his next shed. Just took some time and effort...I didn't even get bitten, lol.

Rainbows are one of the most humidity-tolerant species I know of, so I'm not so sure this is a humidity issue. (In fact, rainbow are far more likely to suffer ill effects on the low humidity side than the high humidity side.) What I'm still unclear on from the picts and description is whether this is just a few isolated scales (probably afflicted with a fungal issue), or a systemic issue where the spots appear in many locations. Alida, would you mind clarifying, please? Thank you!

It is only two isolated spots

Probably fungal then. When it once happened to me, I dabbed with betadine then applied a topical anti-fungal (over the counter althlete's foot cream), which I alternated with neospirin just to be sure. It resolved itself within a shed, and even the scale damage was gone within the following shed. Good luck!

just an update. She has since shed and is good as new thanks so much again for your help! I will definitely be keeping an even closer eye on my husbandry.