Originally developed by NASA in 1966, memory foam, or temper foam, is used in mattresses and mattress pads because of its unusual viscoelastic properties. It is soft, absorbs impact, warms with heat and conforms to the shape of the body providing support when sleeping. When pushed into shape, memory foam will retain that shape for a period of time; however, because of its open-cell construction, the foam will return to its original shape, allowing creases, lumps and bumps to disappear.
Spread out the mattress cover on a flat surface, and allow it to stand for 48 to 72 hours. The memory foam, without any exterior pressure, will return to its factory-original shape.
Apply light heat to the lump by laying on the area with your body and letting it absorb some of your body heat. Massage and shape out the lump when the foam is warm. Leave the mattress topper alone to return to its original shape by following Step 1.
Flip the memory foam mattress pad over, and use it flipped for a few weeks, working out the lump periodically as the mattress pad warms to your body temperature.