The olive oil could very well be the reason the scales are coming off. You need to order a can of Provent A Mite and treat the enclosure with that. You DO NOT spray this on the snake. I'm pretty sure the mites are still there as reptile relief only kills the mites you can see. There are probably eggs still in your snake's enclosure. I would soak the snake in warm water with one drop of Dawn dishwashing liquid, this will help rid the snake of the mites.