I have never done this inside the UE4 engine but wrinkle maps to me sound like a custom sculpted highres model version baked to normal maps and blended in using a tension map based on edge length.
You can export things like that probably with the SOUP plugin for maya during animation baking (since measuring that in realtime might be an overkill).
Or do it a little simpler and just have custom attributes (that get exported with facial animation) tied to blood flow and wrinkle maps applied on certain areas.