Sounds like an allergy to your deodorant...try an unscented brand like dove..I have the same problem...I used to use scented deodorant but that was the problem....
to fix the actual rash the best remedy is the home remedy take cornstarch and brown it in your oven...apply to rash use nothing else but cornstarch...like maybe when you are at home no other products, and wash off your pits getting all deodorant off..this will remedy the problem overnite!!!if not the next use should depending on how bad...this works on all heat rash...and is safe for small kids and babies too...good luck
to fix the actual rash the best remedy is the home remedy take cornstarch and brown it in your oven...apply to rash use nothing else but cornstarch...like maybe when you are at home no other products, and wash off your pits getting all deodorant off..this will remedy the problem overnite!!!if not the next use should depending on how bad...this works on all heat rash...and is safe for small kids and babies too...good luck