FSIL was here a few weeks ago and made a comment about how much our cat seems to be scratching at his neck, and doing that bitey scratch at the base of his tail. I got and gave him some flea medication (Advantage 2) JIC. Since then I've been checking with a flea comb and have found nothing. But I'm paranoid now that he still seems to be scratching a lot. I never noticed it unil FSIL said something. Should I let it go to he's just itchy or should I be concerned enough to take him to the vet? He's an indoor cat btw though he loves to sit in the window sill when we have it open.