I would absolutely recommend against using any prescription (or really other) topicals while on Accutane, unless you consult your physician first. This could result in severe burns or other issues, which will create more intense problems than what you have now. Using products concurrently needs...
I often use Silicone Microdroplet Therapy for acne scars while I am treating with Accutane. I believe it to be safe and effective, as well as very long-lasting. It is best to discuss this with your treating dermatologist as he or she will be the one performing the procedure.
Accutane can make you more sun sensitive and at this point in life, you are not getting freckles, you are getting sun damage. On Accutane you must wear daily sunscreen - it's very important. As to your other questions about length of time for the medication, consult your prescribing physician. 4...