If you can, grind that pan back as far as possible while still covering the back edge with the front of the frizzen. Then polish the pan to mirror smooth. You want to get powder as close to the touch hole as you can, while leaving air between the powder and the hole so that the rising heat will go into the touch hole rather than be above it. YOu might be able to angle just part of the back edge of the pan some to get closer to being under the hole. If the hole is too far back( as in over any portion of the lip of the pan at the rear, ) I would plug the hold, and redrill the touch hole in the proper location. That was done on my .50 cal. rifle when it was converted from percussion to flint.