Y’all my son has a small diaper rash ( I think that’s what it is) near his sack. Well I’ve been…

Y’all my son has a small diaper rash ( I think that’s what it is) near his sack. Well I’ve been doctoring it and it’s not getting any better but for the last two days the skin around the head of the penis is read and agitated and he can’t stand for me to touch it or anything.... I will post pics in the comments. But any advise would be great!