I've been using Isotretinoin 30 mg for 3 months but it's not working. Is there an alternative?

I recommend you discuss increasing the dose.   30mg is a pretty conservative dose, so I would see if your dermatologist would like to go up a bit.  Most of my patients end up on about 80mg daily if they have fairly severe acne.  Good luck, you should have great results once you get to an effective dose!

Isotretinoin almost always works!  You just need to be patient and either increase your dose or take it for a longer period.  Consult with your doctor the approach they like the best.