I agree that it is a relatively sizeable portion of the bag so I don't suggest you fix it yourself. The best option would be to bring it to the BV boutique. BTW, they might tell you to wait 6 months since they'll have to send it back to Italy. At least that was what I was told when I brought my wallet in.
I don't think spraying an aerosol protectant will help solve the fraying either. Those are just meant to prevent dirt & stains on the leather.
Your bag looks like it's made of Cervo leather. Is it? This "fraying" tends to happen on the "thicker" leather strips like Cervo and Nappa Umbria (hence my Sloane comment earlier).