2 months and 2 weeks on Accutane and see no difference at all? Female teen.

I've been on accutane for 2 months and a half now with moderate reoccuring cystic acne, but i see no difference, my skin is not dry at all and just less oily. I weigh 125lbs and i'm 178cm I took 30mg for the first month then 40mg and now started 60mg as my dermatologist was concerned i wasn't dry and i am still getting new pimples maybe 5 times a week, like before. . I'm wondering if Accutane may not be working for me and whether i should continue as its very costly for me.