Hi Dave,
Using olive oil really isn’t benefiting Piper as it’s not treating the underlying condition and by removing the scabs, you might be continuing to irritate the skin. From what you describe, a proper flea treatment (3 months at least) should get done to be sure that’s not the issue. Cats are such good groomers that she may be eating the fleas before you see them. A skin care ointment could also be causing him to lick more as he wants to be clean. Otherwise, allergies are the most likely cause and some proper diagnostics should be done by your vet including skin scrapes to rule out mange mites and a food trial to narrow things down. They would have some better suggestions for medications after a complete exam.
Best of luck,
Dr. Ryan Llera