
Worst thing to do would be to strip more oil from the skin, as this can cause more oil to be produced. Some over the counter creams / washes can can help initially but cause more harm in the long run.
Not sure of her age, but ensure any make-up is removed at the end of the day, use a light oil free moisturiser. A gentle exfoliator and maybe a herbal mask once week would be good.
Tea tree oil can b ok if used locally.
Easier said than done try not to pick!
Finally, if inflammed or infected see your gp.
Good luck!