I was wondering if someone could tell me why when a person eats something very spicy, even though the meat may not be hot, the face begins to perspire.

The reason many exotic foods taste spicy is because they contain the compound, capsaicin. Capsaicin is found in varying concentrations in several kinds of hot peppers. When capsaicin binds to capsaicin-specific receptors on the trigeminal nerve endings in your tongue and elsewhere in the oral cavity, the nerves send a message to the brain that is interpreted as "hot." This chemical sensation of spicy hot is qualitatively distinct from the thermal "hot" sensation one perceives when ingesting heated foods or fluids. Now, to answer your question, when you eat spicy, capsaicin-impregnated food, you activate a trigeminal-autonomic reflex that results in sweating. The presumed pathway for this reflex is as follows: trigeminal primary afferent neurons, to the trigeminal brainstem nuclear complex, to the reticular formation, and from there via an ill-defined, polysynaptic pathway to the spinal cord intermediolateral (IML) cell column. Preganglionic sympathetic neurons in the rostral part of IML (C8-T2) send fibers to the superior cervical ganglion (SCG). Finally, the SCG sends postganglionic sympathetic fibers via the external carotid nerve to the facial sweat glands (causing increased perspiration).