Hello,
It looks like this dryness if due to the benzoyl peroxide in the acne creams. An amount of benzoyl peroxide lotion the size of a pea should be enough to cover most of her face. If her skin becomes red or peels, she is using too much of the medicine or applying it too often. Other treament methods include topical and oral antibiotics, topical retinoids, hormonal therapy, dermabrasion , phototherapy and laser resurfacing. Normally a combination of treatments is followed and if nothing proves effective then dermabrasion and laser therapy are useful. You can discuss these treatment options with your dermatologist.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your dermatologist. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
I have battled with acne forever! I too hate using lotion on my face, but they do make moisturizer for acne and oily skin. I use Clinique and I like it a lot. Also try an exfoliating ance cleanser to get the flakes off. Also I have found that when I dry my face with a clean wash rag every night it makes a difference as opposed to using the same one a few night in a row. Good luck! OH! And going to see a dermatologist is a really good idea. Especially this young because you wouldn't want her to scar.