Use photoshop, create an adjustment/hue layer, with layer mask, set the layer to change the hair to the colour/hue you want (you may want to tick colourize, and remove the tick against keep brightness). Mask out the whole area.
Use a graphics tablet with pressure sensitivity, brush set to 40% opacity, and width set to pressure. then paint the hair back in stroke by stroke.
Post a headshot, and some bored SOB might do it for you