A salicylic wash is a good choice of skincare for oily skin. Differin definitely helps too with reducing oily skin. While it may cause some dryness and irritation initially, most people develop a tolerance to it after a period of regular use.
Some tips that may help to reduce the dryness:
1. Applying Differin only on the oilier areas of the face (usually the T-zone and occasionally jawline/chin for ladies),
2. Spacing out the use if it is too dry (using once every 2-3 nights instead),
3. Mixing it with a moisturiser before applying (usually, a pea size of Differin is enough for a typical sized Asian face)
Acne outbreaks when your period is near is relatively common in ladies. This can be due to many lifestyle factors, but may also be a medical condition that will benefit from early intervention. If the symptoms are really bothering you, I would advise you to seek advice from a medical doctor. Hope this helps!