pins & needles sensation in face & hands post HIM race

Anyone know what this is from or why I got it?  I headed into the med tent just as a precaution. The sensation went away after about 10 minutes of laying down.  They gave me some oxygen,  took my vitals which were fine.  Body temperature was a few degrees high, 99.0. I then started to shiver which varied in intensity, but never anything serious.  Chills went away after I got up and started walking around, covered in tinfoil sheet. The medical staff said that I might have Hypoxia?

The numbness sensation happened once before at the NYC marathon a few years ago.  Although that time it came on pretty hard.  It was much more intense and I felt throughout my whole body, and I had difficulty moving my mouth to speak.  It was scary but I recovered and have been ok ever since.

Anyone ever experience this?  Know why it happens?  How to avoid it?!