5 months post op hair transplant, shock loss or over harvesting? (photos)

If this is shock loss and not over harvesting, it usually grows back between the 6 and 9 month mark. Since you are at 5 months, you need to wait a little longer before a determination can be made.

If it's a shock loss, the hair will grow first and then fall out. If it's over harvesting, it will never grow from the first dates. Unfortunately, I can't tell what it is from your two pictures as I don't see the donor area progress. I hope my information can give you a clue. 

From the most recent picture it is hard to tell if you were overharvested. This is certainly a possibility though and hopefully wearing the hair longer will conceal that. Alternatively SMP is a fantastic option. If it was shock loss you should be able to see some fine hair regrowth on the back of the scalp by now. This would be expected to improve over the coming months.