Rash under boobs

I'm a bit larger chested and I've been getting a rash between and under my boobs where my bras touch my skin. I'm so HOT alll the time I'm constantly sweating even if I don't wear a bra.

I put some deodorant on it, didn't work. If I put anything in that area even if I let it dry, it makes it more damp and sweaty than normal 😬

I had my doctor look at it and she said it's not yeast, to just do my best to keep it dry 🤷‍♀️ that's proving easier said than done lol.

Anyone else having this? What's helping?