The Good: Pyrethrins, for the most part, do seem to be relatively safe for most pets, though dosage is still the key. Many on-line sites list pyrethrins as being safe for cats, and as far as we can tell, used judiciously, they are not too much more toxic for cats than they are for dogs.
Yes: Razor bumps will usually go away when you stop shaving. There are a few things you can do to prevent them in the future. Shave in the shower so the heat can soften the hair, and use a shaving gel. Always use a brand new razor, and shave in the direction that your hair grows. Moisturize after shaving.
Shaving with a bacteria-ridden blade can cause folliculitis, the little red bumps that appear after a day or so, says Jeffrey Benabio, MD, a dermatologist for Kaiser Permanente in San Diego. So switch blades often, and store your razor in a clean, dry place.