Antiperspirants have been used in the attempt to prevent chafing.  The thinking behind this practice, is that an antiperspirant will stop you from sweating. If sweat glands are blocked then chafing or a rash will not occur.
Antiperspirants are for your armpits!
Firstly, antiperspirants are formulated for armpits only.  Cosmetic chemists did not formulate antiperspirants with the intention for them to be used in sensitive areas of our body.  In the event that the chafing has torn the skin, the active ingredient, aluminium chlorohydrate in the antiperspirant may burn the skin, hence why it is not meant to be used on open wounds.  A warning is clearly highlighted in those products that contain aluminium chlorohydrate:
“Do not apply on irritated or damaged skin.”
”Do not apply on broken or sore skin.”
If there is broken skin an antiperspirant can increase the chances of skin irritation and thus skin infection.
Chafing prevention needs to be both safe and sustainable in the long term.