Mass has no direct effect on the surface area of an object. You can increase mass without changing anything other property of an object. Volume, Size, and Shape effect surface area.
Increasing the the surface area of reactants in a solid form, the speed of reaction is increased. The contact between the solid reactants or liquids, gases is faster and more complete.
Surface area does not really affect temperature. It affects heat transfer. A car's radiator has thousands of fins that increase the surface area to increase heat transfer between the air and water....