Extremely Persistent Cyst on Accutane... Cortisone Shot?

I've been on Accutane for a little over four months now. It's working very well; I am not getting much new acne and I only have one active spot left. However, that one active spot has been quite troublesome for me. It's a large cyst right between my eyes that goes through a cycle of popping, scabbing, and peeling before popping again about once a week. It's been doing this for over 2.5 months.

I asked my dermatologist about getting a cortisone shot for it, but he didn't like the idea. He said that it's best to let just let the Accutane do its work. He also said something about the cortisone just getting the cyst down temporarily and that I would be likely to have that spot for a long time afterwards if I don't let it go away on its own... that seemed like BS to me, though.

At this point, I just want the spot gone. Also, with so much damage done to the skin in this spot over and over, I'm worried about scarring, too. My dermatologist gave me some cortisone cream but I don't think it's doing anything. My question is: Does this cyst sound like it should be given a cortisone injection, given that I'm on Accutane? Is my dermatologist right to shun the idea?