Ozone can be very dangerous to both plants and humans, so you need to be very careful. And the infested leaves will not heal but what the ozone does is sanitize the air so the spores get neutralized and don't spread any further. For this you usually need an ozone generator that keeps the level to a specific lower level which kills the spores but not the plant.
Another way to use O3 is to sanitize the room once the grow is over, then you can let it run in order to build a much higher air concentration level, just like CO2 sanitation.
Over time I've quite a number of different attempts of homegrowers using various O3 generators to get rid of PM during a grow - either actively or preventive. Most of the time it failed and the PM came still back, even with expensive automated generators in the price range of +5k bucks. Problem is the O3 simply reacts with a lot of biomecules and so the very plants neutralize its oxidizing potential very quickly. O3 thus is very good to keep a spore-free sterility level in a room that is mostly filled with inorganic stuff, like a laboratory.