The Collaborative International Dictionary of English v.0.48:
Unblushing \Un*blush"ing\, a. Not blushing; shameless. -- Un*blush"ing*ly, adv. [1913 Webster]WordNet (r) 3.0 (2006):
unblushingly adv 1: without blushing; "his principal opponent unblushingly declared victory before the ballots had been counted"