Milk allergy or baby acne?

Hi all, my baby boy has developed these spots on his face and they are only getting worse. He is also very gassy and his farts smell very bad, very eggy. He arches his back and you can tell he is at times in pain due to his full belly. I’m not sure if these spots are because he might be milk intolerant or just simple baby acne? Help please! Also anything I can do against them? See more pics in comments.