he will be feeling pretty poorly on the meds so may not eat till a few days after but keep offering. Trevor would let me hand feed him when he wasn't taking food himself but if you get worried try blending some food - crickets, veg, etc - and letting him lick it off his nose to keep him going
You can help speed up his recovery by
bathing him in avipro, or giving him a probiotic like acidophilis (there's a brand for reptiles someone here should know the name of) to help his digestion. Unfortunately the meds are very hard on a beardie's system and they really do need this
the 10 day course is standard, if it works you should see some improvement, it doesn't always work first time though so you'll probably need another fecal a couple of weeks after he finishes to check how he's doing with them and the vet will prescribe another course if necessary