Fungus on a cat tail

Hello, so today I took my kitten to the vet, because I noticed a non hairy small area on his tail. The doctor told me its caused by fungus. And I shouldn't let him indoors because there might be a chance to catch the fungus. And I should give him his medication for 1 month until the area is recovered. Will that area that is infected will get the hair back grown on it? And when should I let him inside after 2 weeks or so?

From what you tell me the vet said, I suspect your kitten has ringworm.  You can also get an antifungal shampoo that will help him recover, called KetaChlor.  I suggest you google "ringworm" and read about it, and also search here for threads about it by typing in "ringworm" in the search box just below the brown title bar at the top of the page. Ringworm IS a fungus, not a worm, and the hair should grow back when the fungus is gone.  If your kitten was an indoor kitten, you should not put him out because of it, but if he was already an outside kitten, at least you wont have to worry about spores in the house.