I have had the same persistent problems after shaving. I tried many different things on amazon, but what works best for me is to rub in benzoyl peroxide 10% on the shaved area after the shave and dry. Works great everywhere...chest, stomach, butt, gen trim. On days when I don't shave and if I have been sweating lots (butt/gen/waist band area) I just put it on after a shower. Also, I have found that if these areas are tanned from natural sun, this rashing is not as bad (I am white). Hope this helps for you. Don't get the lower strength stuff, go for the 10%!!