What Causes Rash On Face Extending To Chin?

I have a rash on the left side ( different size pimples) of my face that extends under my chin and a small area on my cheek to the right of my mouth. It is itchy and stingy. I've had it for three days now. I try to keep my face clean with witch hazel or plain water and pat dry. Any suggestions on what to do will be appreciated.