Worse before it gets better on ABX?

[Garden]

DD1 was on 6 weeks of Azithromycin. Little/no improvement. Switched to Augmentin 5 days ago. Now leg pains are back with a vengeance (hadn't really noticed they had gotten so much better - guess they had), and we can't get her to brush her teeth. 

DD2 started Bactrim 5 days ago. Restrictive eating/OCD flared, and 24 hours ago, she was switched to Augmentin. Reports confusion/difficulty reading tougher texts that she thinks she would have been able to comprehend otherwise.  Was confused tonight in ballet. 

I thought PANS would respond to antibiotics by getting better quickly, slowly, or not at all, but not by getting worse. Are they both on the wrong antibiotics? How long should I give it?  PANDAS pediatrician doesn't think there should be a herx?

We have two more weeks before they are seen at Columbia.