It is good you have a dermatologist appointment.Birth control can help with acne,but other treatments not involving hormones can too if you find it causes you a problem.
Perhaps if you cannot take estrogen,you could get on spironolactone which also helps block androgens.You will have to be monitored for your potassium levels though (they can get too high on spiro and you will have to cut back on potassium foods like bananas)
Also,some derms won't prescribe it.They may say your GYN has to prescribe it.But you may get lucky.
Have you tried any other over the counter products? Salicylic acid or Benzoyl peroxide?
I used to have bad cystic acne too.I use BP,Differin and 2% salicylic acid facewash.Don't worry,you will find something that works for you