Question:
What are these crusts that form after a hair transplant? When does this happen and how long do they last for?

Answer: 
Crusts that form after a hair transplant procedure are common and can be expected for the first few days up to a week. Crusts are usually from small amounts of bleeding that occur during actual graft implant stage of the procedure. On a rare occasion, it can be sign of infection or poor healing grafts if persists.