I understand your concern. I would first of all stop bottle feed if he is on bottle and give a probiotic powder and racecadotril suspension of powder available in a sachet. hen I would advice to give only breast milk and to keep the area dry and cover with cotton cloth after applying an antibiotic cream.Diaper rash can be traced to a number of sources, including: Irritation from stool and urine. Prolonged exposure to urine or stool can irritate a baby s sensitive skin. ... Chafing or rubbing. ... Irritation from a new product. ... Bacterial or yeast (fungal) infection. ... Introduction of new foods. ... Sensitive skin. ... Use of antibiotics. Take care and come back if you have any more doubts.Regards