Open Question: What can be causing acne on my face?

Hi! I recently started going to gym and changed my eating habits. Everytime I go to the gym after my workout I always go into the sauna for about 15 mins I do this because. It helps my body relax after a strenous work out . But suddenly my face is breaking out in pimples it's seems like one pimple goes away and 3 come on a different spot in my face . I am using neutrogina face wash but it's