Washing your face once a day is plenty. Especially in the winter when your skin tends to get dry, washing it once a day is especially important. While washing your face is a good cleanse and helps to exfoliate and clear pores, it also needs to be done in moderation. This is because the oils in your face and skin need to remain balanced, and over-washing can throw off the oil balance. You should be only washing your face once a day to balance the oils, and make sure that you use a moisturizer after--a skin oil or a daily face or skin moisturizing lotion--to soften the skin and keep it hydrated. You should use a moisturizer after every time you wash your face.
As for acne, over washing can even worsen acne by drying out the face or throwing off oil balance, which can cause your body to over or under produce oils. I would recommend using a spot treatment like benzoyl peroxide cream on the zit, or using a salicylic acid treatment pad like Clearasil to run over zits and reduce redness.