White spot on a black print?
 

Recently I had one my photos printed out very large, and there's unfortunately a very noticeable white spot right in the middle of a large area of black. It looks as if its sort of been dinged or dented in, but I'm not sure when or how this happened, as soon as the picture was printed I put it straight into a large plastic bag. Anyway, so far I've had someone tell me you can get photography 'touch up' pens to fill in the blemish black, but they seem pretty expensive - the guy at the camera shop told me they're basically not worth getting because the price is so steep. So I was wondering if anybody else has had this problem, and what their advice is?

(Sorry if this is in the wrong section by the way, but its the most printing related one I can see)