@cptken I’d try the pinch trick first with a big brush and with dyntopo turned off – if you didn’t see the stream, the trick starts around 1:46:30. If that doesn’t work so well, I’d scale the head verts down in edit mode with connected proportional editing enabled. If you mesh is really dense, this could be a slow (laggy) approach but worth it.
PS: Your orc is looking very good 🤘