Hi, this is a condition we call axillary osmidrosis, or excessive armpit sweating.  The foul smell is cos of the bacteria breaking down the fat. The most effective way is to remove the sweat glands by surgery after mapping your armpit sweat glands using a test designed in 1927 known as the Minor starch test. Botox injections do help but can be very expensive and need repeats every 5 to 6 months. Hope this helps...http://drbonaplasticsurgery.blogspot.com/2020/06/armpits-sweat-gland-removal.html?m=1