Pad Rash??

So I’ve had my period since I was 12 and I’m now 17... but I’ve only used pads. Every time I wear a pad no matter the size, style, brand, or even how many times I’ve changed my pad in one day, I still end up getting a “rash” between my butt cheeks. It really hurts and it feels almost raw. Does anyone have any advice or what I should do to make it stop??