Good deal that is does not appear to be leaking.

By "crevice", I thought you meant a v-cut all of the way through your bank. Instead, are you referring to an erosion channel in the face of your bank?

If so, that is a much better problem to have. Yes re-grading is the correct fix. Any time water flows are channelized, the erosive capacity greatly increases. Your well-graded slope should spread the flow of rain water evenly down the bank, and cause very little erosion until your groundcover vegetation is well established.