Yeah i know how you feel, it's going to feel amazing to finally be done with this medication once and for all. But for me, I started seeing minor improvement around week 6-7... Some people see improvement almost instantly, it's different for everyone! My initial breakout started around week 3 and it was really bad.. If you do experience a bad breakout I'd suggest asking your dermatologist for prednisone. It's a steroid that reduces swelling greatly, it literally improved a day after taking one of the pills. They just don't like you being on it long because it can be dangerous as well.
For me at least, the headaches went away after about 2 weeks on the drug, I get them OCCASIONALLY now but they're small and go away pretty quickly (i've been on tane for a little over 2 months now). Stock up on good lip balm like aquaphor! Your lips are going to become dryer than the desert. Also get a good moisturizer like Cerave or Cetaphil when your skin starts to dry.
My skin got worse before it started getting better, so hang in there if that's the case with you. I know it's hard, but try not to obsess over your skin every day like I did while on this medication, it can make you go insane! Just think of the end result.
I too started on 60 mg/day for the first two months, and my derm just bumped me up to 80mg for I believe another 3 months and then I'll be done... Time flies on this medication, and I definitely still have acne but I know it's improving every week! Good luck!