I just bought a Zodiac flea collar for the stray cat i found, ive never had any cats so i just bought the longest lasting one, and every once in a while the cat would scratch its neck near the collar. Can i just put the collar on any cat or can they be allergic to the flea powder? Right now i really dont have any money to take the cat for a check up but it seems really healthy i also bought some Iams kitten food for it as suggested before. Any one with any advice?