Thank you for your query on Healthcare Magic.
is looking like a transient rash, which are common in infants due to their delicate skin.
Just observe for some time.
Nothing to worry as there are no other alarming symptoms.
You can apply a moisturizer or a calamine
containing lotion externally over rash for soothing effect.
If the rash is increasing, or persisting, or associated with any other symptoms take an appointment to consult your Pediatrician
Hope I have answered your query.