If it's a 5 bolt then 4 bolts should be sufficient to keep the ring on securely. I wouldn't worry too much.
If your OCD is going to bother you, I'd switch cranks or clean up the threads. If there's enough material left to simply chase the threads, I would get a bottoming tap of the appropriate size and use that. If there isn't, consider drilling and tapping a hole of the next size larger.