Coconut oil for diaper rash?

Hey everyone, my baby is 5 1/2 months old and has started to get teeth. He has had diarrhea on and off for about a week and has the worst rash on his bum. I've tried all the different bum creams and just using Vaseline. I also just lay him in a towel to air him out. Nothing has worked. Just wondering has anyone used coconut oil on their babies bums to help treat a rash, if not any good cream suggestions?