2 weeks would be a tad early to stop the treatment, as mentioned. A course of antibiotics usually takes at least 3 – 4 months.
Sometimes, Differin can cause an initial outbreak during the first month or so and if it causes excessive dryness, irritation and flaking of the skin, I would advise using it once every 3 days first and then slowly increasing the frequency to daily.
If you have cystic acne, I would advise draining the cystic acne and consider injectable steroids so as to arrest the inflammation and swelling. This will decrease the risk of subsequent scarring.
Other treatments to be considered include medications to control oil production and lasers.
Hope that helps.
All the best!