I have a young cat (about 4 months old) and she is completely infested with fleas. I put advantage and frontline and they never do anything. I’ll use a flea comb to get some by hand but that only works for about an hour. She stays indoors but I have another cat who is outdoors, but I give him flea treatments as well and they seem to work. Am I missing something? Should I try a flea bath? What should I do??