Diaper rash already

FirstTimeMomπŸ’πŸ»πŸ€°πŸ»πŸ€±πŸ»
My son is 2wks old and ~2 days ago we noticed he's already getting diaper rash😰it's just around his anus and it red and raw looking already. We were using baby aquaphor with each poppy diaper and now are applying desitin. 
We tried to let him air dry down there more hit he just pees or poops on us and the area even more then.Β 
I feel like such. Terrible mom that he's already getting rashes at such an early age😭 what are we doing wrong ? Any diaper tips ?Β