Peter Drummond, Ph.D., and RRDi Mac Member, has a new paper out about blushing:

The effect of facial blood flow on ratings of blushing and negative affect during an embarrassing task: preliminary findings - PubMed
http://www.ncbi.nlm.nih.gov/pubmed/22257642?dopt=Abstract
Expecting to blush is a common source of social anxiety, and is associated with heightened perceptions of blushing and embarrassment. To assess whether sensory cues associated with heightened facial blood flow are an additional source of anxiety, the vasodilator niacin (100mg) or placebo was adminis …