I assume she has been prescribed metronidazole gel which is a topical antibiotic and is usually effective but should it not work effectively she may be prescribed tetracycline or an oral retinoid drug....could be several weeks before it clears. Rosacea has been known to come and go over a period of up to ten years.......time of course will tell.
Little anyone can recommend apart from your doc.
Sorry can't be more helpful. Best wishes, Mike.