I have the same problem!
I take isotretinoin for 2 months now, and not a little amount becouse I take 1-2 pills 20mg. I see that most of my skin is getting better, but I have this bumps on my jaw . But they don't make pimples usually. they are, they sometimes are pink-ish and sometimes hurt, but then they get smaller.... and then they come back :v I just hope that as rest of the skin is getting better, I will have less of this bumps too .