Rash on face --- allergy????

I have given him spaghetti the past 2 nights. The rash started out as a dot under his lip and there's more redness there and now on his cheeks, eyebrow and almost his ear. They're just little spots. It hasn't taken over his face. I thought it was a drool rash. Now I'm not so sure. What do you think? It's hard to retroactively remember what all I did. I thought it started before I introduced spaghetti. The rash doesn't seem to bother him. Can I put lotion?