You probaly cant keep it recurved during the early stages of forging. You would have to forge it in it's general shape and REFINE it into the final shape.
Lots of transitions take place during the forging of an object. It might look good one minute, then look pretty ugly, then good again. You are the decider. You determine the out come.
For a blade shaped object, I try to first start the point, then start distributing material in it's general proportion and shape. When it becomes recognizable as the spear point, just refine it by heating it and hammering and straighten it, then grind it to final shape.
What kind of haft attatchment will it have?