FYI, Sevin dust is bad for bees, if that’s something that bothers you.
I don’t know about the age of the kitten, but my dog has had horrible fleas this year that Frontline didn’t touch but Revolution has really done very well with.
Zsofia, I didn’t know Sevin was bad for bees. I will make note of that when recommending it. I only use it around the foundation of the house and will make sure not to get it on blooming plants.
I love the Dope! I learned something today!
I hope there isn’t a next time! The reason I used the shower instead of a sink was because while I was showering the kitten, my friend was spraying down the rest of the place. The bathroom sink was a little too small to hold a squirming little bugger.
I’d like to thank everyone for their advice though, even though I neglected to say it in my first update.
I really really hope the fleas die off soon and I can stop worrying about them. Both cats are indoor cats. Fleas was actually one of the reason I kept them inside, along with racoons, stray dogs, and other cats, to protect them from those nasty things. Too bad it didn’t work and the fleas found their way in. 
Oh, and there should be pictures soon, I took pictures of the poor little kitten while he was wet, and he looked so small and almost rat-like. It was terrible to hold him against me and feel him shivering. On the bright side, he happily munched on some food five minutes after he was all dried off, so I don’t think he was too terribly traumatized!
We use Frontline on the dog, which, according to the vet, treats the house and the yard, and thereby protects the cats.
We treated the cats once. We’ll just treat the dog from now on. 