[cypher]

Well done for giving Alby the loving home he deserves.

I would imagine the smell will wear off with time, taking him to the vet could be stressful for him & unless he is showing signs of respiratory problems there won't be anything they can do so I would just keep an eye on him & see how he goes.

Hamsters don't get fleas & the treatment could be harmful for him, that may in part explain the excessive grooming, does he have a sand bath? I'm not sure if long haired hams are ok with sand (chinchilla sand, not dust) like others hams but I don't see why not & it could really help with getting his coat clean & free from odours or residues again.

They will often groom excessively when in a new place or after a cage clean, anything with new smells basically or with their scent removed, it's more about spreading their scent around so it could be partly that too.

I wouldn't bother with getting a ball, just bin the old one & let him play in the fort you made or any safe play area/playpen which will be much more enriching for him & give you more opportunity to interact with him.