What Causes Pain In Cubital Fossa Radiating To Base Of Thumb?

After giving blood last week, I have numbness and tingling in the musclulocutaneous nerve dermatome. Generally there is a numb feeling in the distal anterior forearm. Whenever I stretch my arm, like in demonstrating a thoracic outlet test, I feel a sharp needle like pain going from the cubital fossa to the base of the thumb. Should I be resting the area or remain active? would a hot or cold application be better?