Hi, Lauren54b.
I'm glad you decided to reach out on Apple Support Communities. If I understand correctly, your Walgreen’s Balance Rewards app isn’t tracking your activity through the Health app on your iPhone anymore, so you aren’t getting credit for your activity. If we’re on the same page, I can certainly understand why you’re wanting to get that working again.
You mentioned you’ve already tried disconnecting them and allowing the connection again, but it still isn’t working. Did you tap the “Balance Rewards for healthy choices” icon on the home screen of your Walgreen’s app to log in? You should have been alerted to connect the Health app to your Walgreen’s app from here.
If you were alerted and successfully connected the two apps, are you seeing activity being reported in your Health app? If you see activity here, can you open the Health app and tap your profile on the top right corner? In Apps, do you see the Walgreen’s app? If so, do you have all categories turned on here?
This Walgreen’s article may help:
Apps & Devices | Balance Rewards for healthy choices® | Walgreens
Best Regards.