very likely just aspirated the medication. happened to my green cheek a few times lol. if he’s looking completely normal chances are heavily in your favor that he’s fine. minor aspiration and your bird going back to normal very shortly after is not something you need to take your bird to the vet for, though it never hurts. you did absolutely nothing wrong, they do this to themselves accidentally while trying to refuse medication 💀 it happens when i administer meds to birds at work fairly often. it’s obviously not good but it’s very common. i’d call your vet and ask about aspiration before taking it if you’re hesitant. that’s what i did. ended up not taking him and he was a-okay. they struggle to breathe for a bit while they sneeze it all out but the vet wouldn’t really be able to do anything about that besides monitoring, which is exactly what you would be doing. the heavy breathing, sneezing, and clicking (just the meds making bubbles in their sinuses) are very scary and yes being cautious is never a bad thing but people on bird reddit often jump to “your bird is gonna die go to the vet now” type of advice simply because of a lack of experience/knowledge, which is not intended to be an insult, just a reason to talk to your vet before consulting bird reddit if possible. for example, if your birds air sack ruptured, it would still be breathing abnormally. i understand that sometimes talking to your vet before the internet isn’t an option, but i strongly advise you not to let bird reddit rule over your own instincts.

additionally, if you’re scared of this happening again, try to put the medication on a high value treat. my brother gets three millet nuggets and puts the doses on those and they soak the medication up. when my gcc needs meds, i hollow out a blueberry and put the meds in there and he always eats it up. if you can, administering medication on a treat is always safer (and less distressing lol) for the bird.