I've been waiting a few days to respond again to see if my regime was working.
After a few nights (only -- not daytime) of being "drydocked" with the meds on her shell, I can see changes. The white spots are gone. However, now what I see is what looks like the top layer of the shell (the layer with color) appears to have been eaten away by whatever the white was. (See below.)
Does this mean I can stop the med regime? If not, when?
Or should I take Turtle Girl's advice and see a vet for the medicine that coats and moisturizes the shell?
*****
To those who think the shell had been rubbed off: The reason I didn't treat this earlier is I thought that that was what happened when she jumped out of her tub the wrong way (she has a ramp) and landed on her back. But I realized that it wasn't the case when I saw the nearby white dots.
Shedding suggestion: That back part was the only part that was white. It has nothing to do with shedding as she has shedded before (not yet this year) and there was no white then.
It's not exposed bone as it was superficial and the newer dots were to the side, where there's no bone.
Here's her shell as of today. Note what was opaque white is now gray and looking like one level down.
http://i558.photobucket.com/albums/ss23/leeduk/day4.jpg