Were you surprised by the number for the surface area of your subject's skin? On an average adult, the skin is approximately 2,800 in2 (or about 18,000 cm2). Accounting for a little error here and a little too much paper there, the amount you estimated might be a little higher than this.
When you multiply the surface area by the pressure, the number you get is really huge (ranging from tens of thousands for pounds to hundreds of thousands for newtons). This really big number is caused by the force of air pushing on your subject’s skin.
All objects on the surface of Earth—including you—reside beneath a huge ocean of air: the atmosphere. The atmosphere is composed of colliding gas molecules. The push caused by each and every colliding molecule adds up to air pressure. Air has a pressure of about 14.7 lbs of pressure per square inch (psi)—that’s 10.1 N of pressure per square centimeter, or 101.35 kilopascals at sea level. Since air is smashing into every single square inch or centimeter of your skin, the equation area x pressure = force results in some pretty sizable forces.
An average adult's skin of approximately 2,800 square inches is under pressure of 14.7 psi—which makes a total of 41,160 lbs of force.