My mechanic is of the opinion that there is sufficient spar injury to require blade replacement.
On that basis, I have notified the NTSB. For those who don't have NTSB part 830 memorized, 49 CFR 830.5 (11) defines one of the immediately reportable incidents as:
Damage to helicopter tail or main rotor blades, including ground damage, that requires major repair or replacement of the blade(s)
I also gave the FBI an online report, in case this really was somebody shooting at me (they should be able to determine that definitively). Not entirely sure if it's in their jurisdiction, but violence directed at air commerce sounds to me like it might well be in their ballpark. I'll let the county sheriff know if the FBI doesn't show interest.
The search is underway for a suitable replacement blade. If you happen to have a serviceable part 47-110-250-23 lying around, please let me know (yellow tag and service/hours records, please). The damaged one was only about half way through its expected life limit, so it's a real shame to need replacement.