rash with smell in belly button?

is now spreading outwards. I noticed the smell first and wondered if it was coming from down below. In the shower the water stung me and I saw there was a redness in the tummy button area and the smell was from there as well. It smells nasty. The raised redness is slowly spreading outwards from haf an inch to an inch and now aiming for 1.5 inches. It's slightly itchy at times but hurts too much to scratch.

Despite the shower it still smells a bit. I dealt with it with sudocrem but it made it worse.

I think it needs drying so have had tissues pushed in and over it and that's not helping either.

What is it? What should I be doing about it? I don't have time to see any doctors this week but want to start treating it.