I don't take my patients off a regimen until they have had clear skin for at least a few months while being on the medication. It's not a matter of weeks, it is a matter of the cumulative dose of the medication that you received. My assumption based on your question is that you did not receive enough total medication and you are not done with your course. I'd suggest speaking to your dermatologist. "This answer has been solicited without seeing this patient and cannot be held as true medical advice, but only opinion. Seek in-person treatment with a trained medical professional for appropriate care."
Some people need more than Acutane to fully clear skin, I suggest speaking to a well trained cosmetic dermatologist. Cosmetic procedures during treatment may improve results --microneedling, peels, clear + brilliant etc. Best, Dr. Emer.