paresthesia

An abnormal sensation of the skin (tingling, pricking, chilling, burning, numbness) with no apparent physical cause. It happens when sustained pressure is placed on a nerve (from sitting with legs crossed for too long, or fallen asleep with an arm crooked under their head...) . The feeling quickly goes away once the pressure is relieved.

Also known in English as "[body part] falling asleep" or "pins and needles".