How do you know if you have damaged grafts?

It is best to contact your surgeon for post surgery issues and care since all doctors have slightly different instructions. Your surgeon knows the specifics of your surgery and can best assess your recipient area.

Thank you for your question and photos
the number of grafts a patient will need depends on the thickness of their hair and the extent of their hair loss, which can be determined by the Norwood Scale below.
During a hair transplant, grafts are usually removed from the ‘donor area’ located on the back of the scalp and relocated to a balding area. The back of the scalp makes a good extraction area due to the high volume of hair follicles that congregate within that region that are not affected by the balding process. Specialist surgeons will remove a small amount of tissue that can grow hair and relocate it to the desired area of the head without damaging them.

You are doing the right thing to wash your hair gently, remember don't pour shampoo directly into the transplant area, do not grab it vigorously, don't scratch the hair in the transplant area to prevent hair from falling out. 

Hello, good question!! It’s OK to be “paranoid “ as you say. You just had a big procedure done and its natural to worry if you’re doing things correctly. From what you described I don’t think you have damaged anything. At this point wash gently and you should be ok.

Not from pouring water. What you are doing is perfect. Keep working at it to keep the crusts away. Even running your hand over the grafts at this point won't affect the result. 

It sounds like you have not caused any damage to your grafted hairs. It´s no problem being a little cautious either. The first few days the grafts are the most vulnerable. Until they bed themselves into the surrounding tissue. You need to take care especially in the first week. Gentle washing over the scalp and not cause any traction over the grafts. Low water pressure and ideally just warm water from a cup is best. 

It seems that you are doing the right thing by gently washing. The grafts are not well fixed in place the first few days, but still they are stronger than what people imagine. Therefore gentle washes are not a concern for damage. 

From what you are describing, I doubt that you have damaged your grafts. Gentle washing to keep the crust off is the right thing to do