I feel for you buddy. Same thing happened to my new civic - the same hailstorm this Sunday morning. Even though my car was parked inside, the tilting angle has caused 4-5 dents on the trunk and one on the roof as well.
Unfortunately there's no really effective solution. Trust me, I have looked around. Almost a year ago, same thing happened with my brand new corolla as well. Couldn't find any effective solution. You just gotta live with it. Don't try any denter etc. Just live with it. And for next time, keep a good thick car cover with yourself. It helps minimize the effect. The hails are not that heavy but their velocity with which they hit is just too much, which causes the dents. A thick car cover can absorb the impact somewhat.
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