If its much of a nick, I would replace it. You don't say what its on but if its on a generator, I've seen them save engines before just by doing their job. Also, certain ones had an update replacement because they wouldn't work when they got some age on them, especially if the oil wasn't changed regularly.
To look up Honda parts you need to have the VIN number off the engine block. Stamped in, sometimes with a center punch.
The VIN number has 4 or 5 letters followed by a 7 digit number, and usually there is another 3 or 4 digit suffix, sometimes printed below or above it. After the 3 digit number there is sometimes an asterik. (*) The Asterik is not used as part of the part number.
Example: GJARA 1234567 S3A*
(This # from memory, Think it is for a GCV190)
It takes all these numbers for the parts man to get to the right pages in the electronic parts book. The oil alert will be there.