I had trouble getting the Advantage up high on the neck on my ex-feral cat. It's so hard getting it on him; I have to sneak up on him. He gets horrible allergic dermatitis from flea saliva if he isn't treated. I'm going to San Diego next week and I can't bear to think of him suffering if the treatment doesn't work. I got it on the back of his neck but just above the shoulder blades. Can he lick there?