Hello, girls, could you tell me if anyone has had their child have an …

Hello, girls, could you tell me if anyone has had their child have an allergy to formula? How does it manifest? My baby doesn't want to take formula today, he barely ate all day. We are 5 months old, takes a bottle with a cry but not always, sometimes like that too. A little red spots appeared under his eyes, and on his face a bit, on his beard there is some too, but as the pediatrician said, it's from saliva.