The only way i can think of recovering the events is possible if you have them in kafka. What is the retention policy of the snuba-related kafka topics ? If you have events in kafka, you can do something like this:
kafka-consumer-groups --bootstrap-server <kafkahost:port> --group <group_id> --topic <topic_name> --reset-offsets --to-earliest --execute
This will execute the reset and reset the consumer group offset for the specified topic back to earliest kafka msg you have in kafka. You’ll need to this for all snuba related topics.
This way snuba consumers will reread those events and start inserting them to CH.