Question Masking color over texture

I have these 4 properties:
Main texture
Mask texture (black & white)
Color
Vector1 Intensity

I need to overlap on my Main texture, the Color, where the white parts of the Mask texture are. The Intensity will define how much of the color will show.

Example:

Main texture: Skin texture
Mask texture (black & white) (white spots where the cheecks are)
Color: Red
Vector1 Intensity: 0 to 1

As the user changes the Intensity between 0 and 1, I want the character to blush, making the Color appear in the designated white areas of the Mask texture