My twelve-year-old cat had (and still has?) fleas. The exterminator has sprayed my house twice, and I’m alternating every two weeks between treatments of Frontline, Advantage, and Comfortis. It’s been several weeks since I’ve seen any fleas, but Gremlin is still scratching and grooming herself excessively. Are the fleas really gone? Is there anything else I could be doing? She is my only pet. She is strictly indoors.