IT MAY HELP TO TRY TO KEEP HER FACE AS CLEAN AS POSSIBLE.  MANY PRODUCTS BY AVEENO OR NEUTROGENA ARE HYPOALLERGENIC THAT MAY HELP WHETHER IT IS HEAT RASH OR ACNE.  IF SHE SWEATS ALOT, HER SWEAT, WHICH PROBABLY CONTAINS A LOT OF SODIUM AND CHLORIDE, MAY BE GETTING INTO HER PORES AND CLOGGING THEM, HENCE PRODUCING THE ACNE.