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.
Molluscum contagiosum may go away without treatment. It may take several months to years for the infection to go away. You may need a pill, cream, or gel to help the bumps go away. People with a weakened immune system may also need medicine to help their body fight the infection. You may need the bumps removed by a laser, scraping them, or freezing them (cryotherapy).