Nice job. From experience its definitely not the end of the world if you take the right steps and don't panic. I have two that suffered a ph issue similar to you. Dying leaves and serious purpling. Now they're about 2-3 weeks into flower. They didn't hermie and the new growth and preflowers look awesome. It took a few weeks to straighten out ph though so be patient. What are you doing to correct the ph?
I'm watering with pH'd water. My tap water is crazy high (like 8-9) because it's well instead of city water so I used some pH down to get it around 6-6.5
Update 4: 26 days from seed She started her preflower stretch today, I woke up and checked on her and she'd grown the inch that was between her and the light. She got burned a little from where she was touching but I lowered her a little and raised the light a little. You can see the pistils on the main bud, and also where the tips got burnt from touching the light. I watered her today, and that's why she's looking sorta droopy but she'll perk back up by tomorrow. I hope I don't lose any more leaves due to the pH problem, which I've gotten under control, but only time will tell. I switched my 6500k bulb to a 2700k Saturday, when I saw the pistils.