Foam mattress pads can be just a regular foam pad, a memory foam pad, or an egg crate foam pad. Since foam in general absorbs a lot of liquid, when drying, it is important to dry them thoroughly since any moisture left can be a breeding ground for mold, mildew, and bacteria. Also, due to their unique material, you cannot just toss them into the dryer as you might a regular pad.
Pat the mattress pad dry with a clean towel. Soak up as much liquid with towels. Foam pads can be wrung or twisted to get some moisture out, however you should read over the instructions on the label sewn into your pad to be sure.
Use a hair dryer. If your pad is only wet on the surface, after soaking up as much liquid with a towel, you can use your hair dryer set on low. Use about 6 inches away so you do not damage the foam.
Air dry the mattress pad. If you are air drying it outside, place your mattress pad on a clothes line or use a few chairs to hang the pad across. If the pad is in direct sunlight, this will help it dry faster and may possibly kill more bacteria and germs; however, it will cause fading. Fading will not harm your pad or affect its longevity or performance. If you're air drying your mattress pad inside, lay it across some chairs and allow it to hang. Open the windows and use a fan to make the drying time faster. After a day, if the pad is still wet, flip it over.