I had hail a few years ago. The trees fine one day and a week later when I returned to the orchard I noticed tattered leaves and big tears in the fruit. I was puzzled as to the problem so I asked someone who lived nearby and they told me about a hailstorm that occurred in my absence. See photo above.

The apples turned out ok but had some scars on it as they developed. Luckily my hail damage occurred in June when the fruits were not real large. Having hail in August when the apples are larger and softer would cause a lot more damage.

I don't know how the fertilizer would help as tattered leaves will not grow back but any new leaves that emerge the rest of the season should be fine.

If you have apples and you got hail damage this time of year, be on the lookout for fireblight!