For perspiration treatment , the actual cost can depend on the surface area your are trying to block . A smaller person with small hands , pequena ( underarm ) skin , or small feet will require less medication than a person with larger hands , pés, underarms , etc. This is because the Botox is injected in very small amounts , typically .05 ml per site with 2-4 units per site . The Botox will diffuse a short distance in the axillary skin , geralmente cm ( half inch ) in all directions . By overlapping the circles of diffusion , it will cover the entire axilla if you inject small amounts spaced about cm apart . A typical underarm will require 100 - 120 units total (50 - 60 per armpit ).