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.
This can cause irritation, pimples, and even scars. To minimize razor bumps, take a hot shower before you shave, pull the blade in the direction your hair grows, and don't stretch your skin while you pull the razor across it. Always use a shaving cream or foam. Rinse with cold water, then apply moisturizer.