I need answers. PLEASE HELP

So my 11 month old son as been having bowel movements at least 5 times a day since December 26th. After a week of constant poopy diapers I took him to the doctor and they said he is fine as long as he isn’t throwing up and if he doesn’t have any blood in his stool. He did say if it continued to bring him back in a week or so. A week or so passes and now my baby has a raw booty from pooping. It’s always a different color, runny or a soft texture definitely not as solid as they use to be. I make an appointment with his doctor and she says that she isn’t concerned because his weight is fine and he isn’t bleeding or vomiting. My question is has this happened to anyone else’s little one? My baby is in constant pain because now he has this bad diaper rash that I can’t control. I keep him dry and clean. Have also tried a variety of creams. Someone help me I don’t know what to do at this point.