Do NOT try to dress out the prop yourself. Even a small nick can cause a
prop to fail in flight. If this happens at full power, the engine can be
ripped off the airplane in less than a second! Without the engine, the
airplane becomes extremely tail heavy and a violent crash is unavoidable.

Certain types of nicks on certain models or propellor are fixable. A
licensed mechanic with a powerplant rating knows how to properly dress a
prop if it's possible, and rebalance and repaint the prop. Don't try to
paint the prop yourself. Even a small amount of paint on one side can
seriously unbalance a prop. Some propellors are balanced by simply
applying varnish to one side...that's all it takes! Get a prop shop or a
powerplant mechanic to work on it.

wrote:
Filing or dressing out prop nicks is a job for a licensed
mechanic, since there are legal specs that must be adhered to, and the
prop manufacturer has more dimensional limits that need to be checked.
They learned these things the hard way; don't you go doing the same.
The right sort of nick, in the right place, given enough time in
operation, will result in a crack that could see a chunk of prop
disappear, and the imbalance could tear the engine off the airplane.
The airplane will not glide with its engine missing, so nicks need to
be taken seriously.
I've seen some badly repaired nicks that actually make the
prop more likely to fail.
Dan