Note, the Dynamesh number is relative. It depends on the size of the subtool. Small subtool at 100 dynamesh would be totally destroyed. Whereas very very big subtool dynameshed at 100 might still be too dense.
Like guys are saying, drop down to lower subdivision. If you're using Dynamesh, you shouldn't get higher than 100 before achieving the likeness. Creating a likeness is a really hard process, which cannot be achieved without anatomy knowledge of the face. You can't just copy the shapes, you need to know what creates them,…