You could also mask the unaffected areas on your target model, line the heads up so that the affected area matches as close as possible and then run a Project All in ZBrush. You will likely have to do some relax smoothing (hold shift to start smoothing then release shift without releasing your mouse button/lifting your pen) to soften the transition from the morph to the masked area but it should work.  Joe's method should work too but if you ever want to try it in ZBrush again, that'd be how I'd do it.