Once the thrush has been killed, treatment will get easier. Topical treatment two or three times a week should be sufficient medication. You will still need to be diligent about cleaning your horse's feet and keeping his stall and turn out clean and dry. Over the next several months, the frog tissue will grow out and appear normal, as long as there is no relapse. With aggressive, diligent treatment, the prognosis is good.
Most horses recover completely.
The more serious the infection, the more guarded the prognosis. Keep your horse's stall and turn out clean and dry. Thoroughly pick out your horse's feet every day, whether you ride or not. Dig all the way to the bottom. You cannot hurt a healthy foot with a hoof pick.