Last night (March 26, 2013) was cold here in S. Mississippi. A low of 28F was reported in Hattiesburg. Other locations reported similar temperatures. Tonight’s temperature is going to be similar. We may not know the full extent of the loss until the weather turns warmer over the weekend. I was in Natchez yesterday and saw some significant damage there on unprotected blueberry blooms.
These papers (http://naldc.nal.usda.gov/download/27362/PDF and http://journal.ashspublications.org/content/124/4/337.full.pdf) have some good information on Rabbiteye response to freeze damage from an earlier events.
Botrytis may also become a problem after freeze damage to blooms. This fungus attacks blooms and fruit mainly but leaves and stems can also be infected, so a fungicide application may be considered to help control it.
As I receive more information on the status of the potential damage I will pass it along.