I treated the kittens about two weeks ago with Revolution per the vets instructions for the fleas they had. That got rid of them, temporarily. I was under the assumption that such treatments lasted for a month. I found fleas on Lennon again yesterday..so what do I do now? Ringo and Quinn (my dog) are going to the vet Thursday, so I am going to ask there... but is it normal for it to not work the whole time?