Are you sure it's pimples?

I get dyshidrosis, which is a form of eczema that shows up as little fluid-filled bumps. Too much moisture brings it on - mostly I get it on my hands from wearing gloves, but I can get it on my forehead from the helmet too. I'm especially susceptible to it this time of year when it first gets warm and my skin has to adapt to the warmth and humidity.

If you think that's what it might be, anything that keeps the area dry will help (think corn starch). Usually if I've got a full-blown breakout I have to resort to using cortisone, but use it sparingly on your face and be very careful around your eyes.