One tip: it is best to optimize your image before applying it in Headshot. Make sure lighting is even and hairdo is not covering the face too much.
Without getting too technical, the skin color of the body is deduced from that of the head. If you edit the face texture later, you may get mismatches.
Especially if you use SkinGen, which modifies the skin materials in various ways, editing the head texture afterwards can be tricky.
You can make adjustments to the head texture generated by Headshot (as shown in the Headshot panel) and that will update all body materials properly most of the time. However, that needs to be done before making any SkinGen modifications.