In the spirit of avoiding Photoshop until absolutely necessary:

A lot of head-fitting texture issues I've encountered are very isolated to a small part of the texture. While I am taking steps in my pipeline to avoid these issues from the getgo, I imagine this is a common issue.

What I would propose is adding a simple brush to the texture-blending part of head fitting that would specifically let you dial in and out the opacity of the texture with the head-color. That would solve most of my issue and would allow a ton of other little cleanups while seeing those affects in 3D in realtime.