Wierd sensations after neck injury

It's six weeks since I was rear-ended by a person doing 25 MPH in a SUV.  Sometime during the first week - in addition to the expected muscular soreness, I started experiencing a number of odd symptoms.  Primarily "icy cold" or "frost-bite" sensations that are transient, intermittent, unpredictable and variable in intensity from just a bit cold to painfully sharp aches.  These are apparently located in too many places to be explained by a "focal" injury - as they happen in my feet, lower legs, sometimes thighs, hands, sometimes wrists and shoulders (outside).  A neurosurgeon suggests it's not serious and will likely go away in time - that he can't imagine any one explanation or area in my body being injured that would cause the symptoms.  He prescribed dexamethasone for 1 week - supposedly as a diagnostic aide.  After 3-4 days on those meds, the symptoms have subsided, but not entirely disappeared.  My family doctor suggests it could be nerve bruising or a result of mild concussion (I did black out mometarily).  Any ideas on what this is?  Has anything like this happened to others due to a similar accident?  Did it go away like the doctors suggest it probably will?  Thanks.