I get a sore butt crack from over wiping, mucous and sweat, I guess it is more or less the same as diaper rash. I use wet wipes after going to the toilet, then pat dry (I do this all the time as a preventative measure) and if I'm sore I apply a barrier cream (either zinc based or like Vaseline).
I get relief within a day from doing this (though it takes a little longer to fully heal, I can feel it's working). The one time it didn't, I needed anti fungal cream from the doctor.