I want to show you the white spots that are appearing on the underside of my chilli plant leaves. It’s not really aphids. The spots don’t seem like something that’s “on” the leaves, but more like they’re on the inside of the leaves.

I’ve had this on chilli plants before, and my conclusion is that the spots show up as a consequence of the plants sitting in a south-facing window and simply getting too warm. Apart from the spots, the leaves seem healthy and the plant seems strong. I usually don’t do anything at all when this happens, except keep an extra eye on the plants and inspect the leaves a bit more often.
The spots are also visible from above on one of the leaves right now.