Orangish brown blemishes on my chamaelobivia

[StarDragon]

My chamaelobivia has orangish brown blemishes in irregular splotches on its main stem & offsets. I originally thought it may be red spider mites, but I found no further evidence of their presence. No mites, no webs, no damage to adjacent plants, no damage to new growth on this one or the other plants. I then thought it may be a fungal infection, but when I researched, it was inconclusive. No images I saw matched quite like the problem my cactus is having. It appears to be getting worse. What else could this be?
I'm having trouble getting the photo to post properly, so until I can, I will leave it at this description. The blemishes irregular, random, & are a light orangish brown & do not appear to have much of a different texture than the cactus skin, perhaps slightly more rough. There is no obvious shriveling or dead portions, & other than the blemishes, the plant appears to be otherwise healthy currently.

[iann]

Mites would cause mottled orange or brown scarring. No webs and no damage at the apex doesn't rule out mites.

Large irregular marks could be cold damage or corking, depending on where they occur.