Disease or not disease?

[ggu]

i have just bought this and couldn't identify its name. anybody know its name?

over the last week, i noticed these small dark brown/red dots on it. (see pic)

i have gone through the pests & disease page but couldn't identify it being frost or pests or diseases.

help & advice appreciated!

[madkactus]

looks like a Fero to me. The cactus is stressed about something. Perhaps not enough light. The spots are not a good sign.