I had my belly pierced about a month ago now and it still seems to be red at the top of the piercing

It's in the process of healing. Puss coming out and itching. Give it time

Are your clothes, like the top of your pants, rubbing against your new-ish belly button piercing perhaps? That can prolong healing and lead to redness and oozing. I would advise you to make sure you wear loose clothing that doesn't interfere with the belly button piercing in any way. Also, perhaps stop cleaning it with salt water and use alcohol disinfectant wipes instead. That is what I was told to use when I got my belly button pierced way back, anyway. 

And if you are seriously worried that your piercing is infected, please have a doctor or your piercer check it out and get some advice. We can't actually see your piercing, so we can only help you that much. 

My belly piercing took a year to heal. It kept getting red and I had discharge coming out of it. I just kept washing it. I refused to take it out, and after a year it finally healed. It's now been 15 years and I never have problems with it. If you can stick it out for a year or so, it will eventually heal.

Hi I hope this helps u

Wash it once a day with clear anti bacterial soap in the shower

Don't play with it

Dry it with a paper towel

And wear loose fitting clothes for at least 3 months so the piercing can heal

I have had mine for 9 full months now and I still clean it in the shower once a day that way it keeps it clean and healthy and it speeds up the healing