Well, first explain to her that this is not her fault. Many people still erroneously believe that acne developed during puberty, even severe cases are somehow the result of poor eating habits. Eating chocolate mint ice cream does not cause pimples. Overuse of makeup or not washing one's face can lead to build up of pores, which most people with acne don't do. Usually it is part of the growth spurt of the body, producing more sweat.
As well, she is in good company. Many famous individuals had severe acne and have been succesful in life. For instance, Bryan Adams the musician, Jon Bon Jovi, etc. If she feels that she is going to be teased about it, let her know in no uncertain terms that anyone doing this to her are idiots.
First, she should see a doctor and a dermatologist if possible. They will be able to determine if it is due to dry skin or oil secretion. So stand tall.
The next is, do not pick or rub them out of frustration or as a nervous habit. Rubbing will only irritate the skin further, which can prolong the outbreak. Picking them will also irritate the skin, potentially leave marks, and if not ruptured and cleaned properly, will develop into cysts that will need to be lanced by a doctor for drainage.
At home treatment can include mild to severe face cleansers specific to acne. Careful not to dry the skin. There is also a small tool that dermatologists use to remove black heads and acne. It looks like a large needle, only with two needle hoops on each end. If anyone is tempted to rupture their pimples, please use this tool.
The dermatologist will be able to see if a topical cleanser is best. There are also antibiotics that can reduce the production of oil by the skin, there are hormone treatments, and other solutions they can give you.