Shock loss in the donor is rarely permanent with FUE. You probably had a fair amount of numbing injections like Epinephrine and these constrict the blood vessels also and for some shock can occur and especially if the patient has a lower pain threshold and more injections are used.
Ideally see your surgeon/clinic for advice as you are very fresh from surgery and they may say to apply Minoxidil to the donor area to speed up growth.
It should come back in but can take a few months to fully do so and your clinic may give you tips on this so try not to worry and just be patient for the growth to come back in again.