Could this be rosacea? I used to get a red face after eating, just like a blush complete with heat. It got pretty bad, progressing to sore, light sensitive eyes, as well as lumpy skin (it's also known as senile acne - charming!). No one knows the true cause, but I'm betting on a change in the gut flora which is creating a toxin. Metronidazole antibiotic clears it up when taken orally but does nothing for the skin when applied as a cream, which indicates that it is killing the trouble making population of the gut flora and in my own case when I started low carb / lots of greens it went away!