Dwarf hamsters hd huge fight, one is badly injured help asap please

[Aine]

So I got two winter White (i think) dwarves in mid-December, they are two girls from the same litter, one is blind and was a runt and the other one is perfectly healthy and happy. I got the healthy one first but I was told they had to be kept in pairs or more so I went back to the pet shop and got her a friend, i wasn't aware that the one i got was blind until a vet visit. They have been getting along so very well until tonight, i went to change their food and water and found my blind hamster bloody and cut up all around her back and ears. The other hamster was pacing outside of the little hideout the blind one was in trapping her. I have them separated in a makeshift cage for the night.

I'm not sure what to do now.

I got them in petmania Ireland
They lived in a crecti 7 imac cage but have just started the process of building a massive DIY cage

Any help is greatly appreciated as I'm quite upset and worried

Thank you 💙

[souffle]

You need to keep them totally separate from now on. They will be absolutely fine alone and usually become much more people friendly. It's common for them to fall out at maturity like this. Groups should not have huts with areas where one can become hemmed in. They need multiple exit roots.
If the injured one has superficial wounds you can bathe with a salt solution the monitor that they heal well but if they are deep and look messy or are very swollen she needs seen by a vet. She should heal well in 10 days or so. A bin cage is perefctly fine for her. Clean both cages out so they can have fresh scent and make them their own. try and keep the cages apart to reduce stress as much as possible. Personally we don't find dwarf hamsters like very huge cages so a decent size but not gigantic will mean you can access and interact with them. They really don't need cage mates as the shop told you so please don't worry about that.