Nizoral after transplant. Could I have damaged the transplanted follicles?

From about 7 days on, there would be very little that you could do to damage a hair transplant.  So, I would stop worrying but certainly inform the transplanting physician about your concerns.Dr John E Frank, MDNew York City

Always check with your doctor if you want to use your own products.  Trying to find your personal medical questions online on the Internet may leave you confused with misinformation.

No worries. You should be fine (and so should your new follicles) if you use Nizoral shampoo 2 weeks after your hair transplant procedure.  Your scalp should be well healed and the follicles in place by then. You will notice the hair starting to shed at some point.  This is completely normal and happens regardless of what shampoo you use.  This is part of the normal process.  You will most likely not notice any new hair growth for months, so do not be alarmed or concerned that you have done something wrong. Good luck

In general, follow the post op advice of your surgeon carefully and let him or her know if you decide to make changes to the plan or have persistent concerns. There should not be a concern about use of this particular shampoo at day 15. By this time your new follicles have adapted to their new living space and are reprogramming to create a brand new hair fiber.

If all of the crusts were off when you used this shampoo, then you probably did not do harm to it. You should always follow your doctor's advice. 

Nizoral is an anti fungal shampoo which is used in some clinics to accelerate hair growth. It is alright to use it after the hair is settled in which is usually after two weeks.