Yes I have a photo of it somewhere on here - I'll have a look! I've had two robos and neither were tame enough to be handled. What I used to do was put a snooze cube inside a guinea pig sized pet carrier. I'll link the snooze cube as well, but something similar would do. I'd have bedding in the bottom of the pet carrier and the snooze cube on top. They used to sit inside the snooze cube in the pet carrier, as it's nice and dark and cosy. I'd take a plastic storage box with me (not particularly tall but that's ok for a robo) with hemp mat in the bottom and I'd take a few bits in a carrier bag (a flying saucer, a tunnel and some food). When at the vets I'd put the storage box on the vet table, with the hemp mat in the bottom, put the saucer and tunnel in it and a little pile of food. Then lift the snooze cube out of the pet carrier (with my hand over the door) and put it down in the storage bin. The hamster would emerge from the snooze cube and investigage the bin, run on the saucer and nibble at the food and the vet could get a good look at the hamster in there, and also manage to pick the hamster up from there, holding them over the bin in case they wriggled free.
The vet was a bit surprised the first time I did this (I did it to avoid stress for the hamster and avoid the risk of them being dropped or running off the table!) but was fine with it.
As elusive says, you shouldn't try any treatment without a vet checking them over. It might not be mites and the treatment can be quite toxic if not given in the correct dose or the correct product or the weight of the hamster not known - especially for a tiny robo. A vet can do a skin scraping to see if it's mites (they need to look at the scraping under a microscope as they're not visible to the human eye).
It's possible also that your robo has an allergy to the bedding which can also cause this kind of thing. What bedding does he have? They can be allergic to any type of wood bedding, even hardwood.