10.5 Month Old Has Diarrhea 😥

My 10.5 month old has had severe diarrhea (we are up to 9 watery stools just today). He was acting fine besides that. No fever. Still has wet diapers, so we arent worried about dehydration yet. The problem is the diarrhea is irritating his skin so badly. We are checking his diapers every 15 minutes so he doesnt sit in it, using diaper cream, dabbing his bum clean instead of rubbing to irritate it less, and only using water wipes then dabbing dry. He is in so much pain every time he goes and we wipe him now. I feel so bad, but I don't know what else to do to help sooth his skin. We tried to just run a light stream of water from the showerhead to clean him instead of wiping and that was still painful for him because he screamed as soon as the water hit his rash (it wasn't too hot or too cold either).

Any tips on how to sooth his bum and help him with his diarrhea would be appreciated.