How critical is it if a pebble blows into a propeller?
This sort of FOD is often not an immediate problem, however introducing any slight knick or gouge to a propeller could be the beginning of a stress fracture. The last thing you want is a catastrophic prop failure whilst flying!

The correct course of action, much like any minor damage to the airframe, is to note it in the logs, have a mechanic look at it, and make the call if a repair is necessary.