Hello doctor my six month old has a red rash by her mouth going down on her chin I recently start feeding her food what's the cause?

Hi Fero Ali, 

cause of rash can be allergy or from picture looks like a insect bite. You can apply calamine lotion over the rash. If there are any other symptoms like fever, increasing rash, irritability, breathlessness immobile consult to your paediatrician. 
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