Um, you'll have to check with the vet on this, I'm not sure what is inside the eye socket so I wouldn't try this if it can damage anything behind. But sugar kills micro organisms. When Warren was neutered he kept getting scrotal infections. The vet would clean them out and resuture and they'd reinfect. In the end we packed the hole with plain table sugar (you clean it out twice a day and apply fresh. Yummy, sugar coated abscesses! Sorry, yucky humour. Anyway, he healed up really really well. They use plain table sugar at Guelph for deep abscesses in horses because they are so sensitive to drugs and sugar is very benign. Again, I'd say talk to the vet. The trick is to keep him from grooming it off (or other rats doing so). For Warren we made a body cast out of tape so he couldn't reach it. Maybe some kind of collar? I know they are hard to keep on a rat but something should work. Maybe taped harness across the chest so he can't get his arms bent up to his face? Jeeze I wish you were closer to pass on some of our homotox stuff from work.
You know I just went back and looked at the photos. As bad as it looks it still looks better then the bloody bulging eyeball.
Hugs to you...it can't be easy taking care of these guys. I've got two sick at home running me ragged but no-one who is post surge. It really takes a lot out of you.