Once it runs out, assess your skin- do you really need to keep taking it?? If this answer is a yes, refill the prescription and keep taking the
Differin(
In relation to taking it "permanently", i recommend doing this self- assessment everytime you fill the prescription, no matter how long you have been using it). If you think no, then try just using the cream without the antiobiotics. If you are seeing your skin remain clear with just the cream, continue using that.