Hello everyone! Can you tell us, we have allergy that doesn't go away …

Hello everyone! Can you tell us, we have allergy that doesn't go away around the mouth. Plus, red dots appeared on the mons pubis. We change diaper only at night and for walks. We fight with allergies constantly ( It appears and disappears. What foods are allergenic? I don't give sweets, only dairy. What should I give the child if I even cancel it? What do mothers give? What do they feed?