You have too much information painted into the diffuse for the normal map to do its job properly. Chuck some of those weird dark lines and spots on places like the bridge of the nose; they look weird and they're doing work that the normal map should.
To see the real issues with your normal maps, just take off the diffuse while you try to figure something out. It will definitely help out a bit. Where are you rendering this? Is it in unreal? Max? Maya? Where? I would suggest using Xoliul's shader if you are using max.