Looks like your baby skin is sensitive and inflamed.needs treatment like keeping area dry from sweating  avoid using over the counter skin creams for such type of skin. There are better medicated creams for sensitive skin for avoiding such problems in future. Currently can try absorb dusting powder if it don't help visit vthe pediatrician.

U need to keep them dry.  They get red due  to sweat accumulation. Use Abzorb dusting powder whenever required to keep the folds dry after cleaning