Vet injected hamster with antibiotics without weighing him first?

[hrcci]

My male Syrian is sick so the vet recommended we give him antibiotics (enrofloxacin)


I asked if they could give them the oral suspension in a syringe but they said that kind doesn't exist in my country, only pills and injections. Before I knew it, they quickly administered it to him via a small prick on his lower back.



Once I left the office, I realized they didn't even weigh him once during the visit nor was I asked for his weight. He's 128 grams. He's doing fine now afterwards and running and eating, but aren't medicines supposed to be administered based off the math of the exact weight in grams? Could this have harmed my hamster? The vet wants him to go in for another injection but I'm worried about it now.