I use canesten cream on those rashes, because they're yeasty or fungal in nature, not bacterial. You can use hydrocortisone on them too (at the same time as the canesten)
I know canesten is used for your hoo hoo, but it works under the boobies too.
You'll keep getting them, Joy, as long as you have skin that rests against other skin. You might find that you get them even more, if you have, say, a layer of skin over your belly button or something.
Really make sure that the area is dry after your shower. Do not use baby powder (it's now made with corn starch which feeds the yeast/fungus causing the rash). To make absolutely sure it's dry enough after my shower, i usually swipe the area with some rubbing alcohol. (i use a qtip for my belly button)
You may want to make a doctor's appointment, because rashes like this are a supporting factor for OHIP paying for some of your plastic surgery. YOu'll need to have your rashes documented with your family doctor.