Need Help

Hello all!
I'm a relatively new Curezone member.
I'm so glad this pet forum is here. I have a year old lab mix.
She's suffering with flea dirt.
I've treated the house w/ different boric acid compounds and will continue to do so b/c of the incubation period and such. She does spend a lot of time outside. Usually I'm with her 24/7.
I've given her flea treatments. I shampooed her thursday and then re-treated the flea compound on her neckbone and tailbone area.
I've used calamine lotion to soothe any dry areas.
Still she scratches and bites.
(She swallows them and i'm treating her w/ herbs, internally. I rarely see a flea on her at all. The vet said a lot of times they stay only 7 seconds, enough to bite, irritate and leave the flea dirt.)
My question is, is there is a topical essential oil that i can dilute and apply to her skin, that will tell these vermin to take a hike!!?
thanks for any and all replies. Please help.
Hollytree & Daisy