What you did is fine.
Good that he is feeling well enough to eat.
He is not in respire distress, just very ill.
If he has taken his meds, personally I would wait and see how he is doing since he has had the puffer.
I would give him (or him and cagemates) a dish a soft food .... to give him nutrition and keep him hydrated
such as: block mush, organic soy formula thickened with baby cereal, ensure, baby food, mushy cooked carrots or sweet potato or peas, etc
Check his hydration (pull up on the skin on the back of his neck or back and see if it snaps back into place - if it doesn't he may be dehydrated), and make sure he doesn't get dehydrated as that can kill
If he is grooming or willing to eat, then he is feeling a bit better
Later, if enough time has passed and you think he needs it, you might give him more Benadryl