If you get shaving rash, it'd be understandable if you thought the irritation on your skin was the result of slicing and dicing it with too sharp a blade. However, as any worker at an Alaskan fish camp will tell you, you're more likely to cut yourself with a dull knife than with a sharp knife. The same holds true for razors. When a razor dulls, its edge becomes slightly rounded, and tiny, imperceptible chips may form along that edge. When you run it over your skin, it now snags on some hairs while passing over others. Add to that the sloughed off skin and hair particles clogging the razor, and you're in for a rough shave.
Wash your razor after each pass over your skin. If you're not getting an easy pass over the skin with your razor, don't think twice about replacing it. Using a dull, dirty razor will make you more likely to pass several times over your skin, agitating it and cutting hairs unevenly. While missed hairs will stick out on the skin, hairs you've given the hatchet treatment to will likely curl and grow back into the skin. The result? Skin that's not only painfully scraped and full of ingrown hairs, but also skin that shows off unsightly hairs that were missed during the shave.
Also, don't forget to regularly take apart and wash your electric razor, if that's your weapon of choice. Roughly rubbing a poorly functioning electric razor over your skin repeatedly won't do anything to bring you a sense of relief.
If you have a bad shaving rash and the freedom to avoid shaving for a few weeks, most ingrown hairs will eventually free themselves when left alone. The same curl that caused this trouble will eventually behave like a spring, and the tightening coil created by the hair's continued growth will pop the hair free of the skin it's embedded in. Ingrown hairs can also be freed using a sterilized needle or tweezers to pull on the exposed loop of hair until the embedded tip comes free of the skin.
Start warming the water, sharpen up your technique, clean that razor and see the next page for lots more information.