Colour your face red

When you embarrass yourself you colour/paint your face red. Red being the colour of embarrassment since people's faces become red when they are embarrassed.

T: "Weather report says it's going to rain soon"
V: "I don't think so, they're never right. Let's go out"
T: "Don't blame me if you colour your face red"
*Starts raining just as we step outside the house*