GUESS NOBODY CAN RELATE:(
Hey! I can relate. I've had mild/moderate acne. I was on spiro and it cleared me up for a while then I just became immune to it. I was also on aczone and retin-a for a time and it never kept my acne away it only helped a little bit. Tretinoin will definitely make you breakout for the first couple of months as your skin gets used the medicine. If you are still getting cystic acne, I honestly would talk to your dermatologist about going on accutane.
I have tried literally every topical medication and nothing seems to permanently cure my acne. I rarely got cysts but my acne was still very persistent so my derm put me on a low dose of accutane. I'm about to start month 3 and things are looking up. I haven't had a cystic pimple since I started treatment and my breakouts are calming down a ton. I know its a scary drug, but a low dose sounds like it would be the right for your type of skin!
Hope this helps