I wouldn't worry over it too much unless it starts to change/get longer as it's likely just in the finish, not the body. I'd wonder a little at how you're handling the bass tho, here's a pic of mine doing what I belive you're describing - On this bass it was the result of me knocking it off it's stand while playing another bass at a show, it faceplanted itself into the stage headstock first creating stress fractures on the sides of the neck pocket. That happened at least three years ago, no problems so far.
