Hello The rash you’re seeing is likely a common type of heat rash (miliaria) or infantile acne. At this age, babies can develop small red or white bumps (like pimples), especially over areas covered by clothing and where sweat collects — like the chest, back, or shoulders. This is very common and not harmful. Usually settles on its own within a few days to a couple of weeks. It’s not contagious, and not due to any allergy or infection.

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