I know exactly what you mean. I have the same problem. My ressolution was finding a good bra that kept your whole breast from touching the skin underneath. Powder and deoderant works, but its the skin on skin contact that transfers bacteria, and creates a warn dark breeding for it. Try, before using the powder, use rubbing alcohol on a cotton ball to dry the skin and free it from oils. Then don the bra, and the underfold of the breast off the abdominal skin.....
If I confuse you, I am sorry. Hope it helps...