Hi there -
Some people, statistically more women than men, have a problem with facial (and sometimes upper chest) flushing for no apparent reason. The autonomic nervous system is the culprit in this, as it acts inappropriately for unknown reasons. The good news (for you, anyway) is that some people have a lot more funny business happen because of this same malfunction, if that's any comfort. Spontaneous flushing is difficult to control, and it makes some people uncomfortable in social situations, but it has no other medical significance.
Hope this is helpful. Good luck to you.
John Kenyon, EMT, CCT
Non-invasive cardiology tech, Emergency and Critical Care technician, Critical Incident Stress Mgmt. specialist