Can I wear a hat 6 days post FUE?

It is best to ask your surgeon about post operative care as each doctor has their unique regimen.   There should be no issue with wearing at 6 days after your surgery.

I think your question is mainly about wearing a hard hat. I have had a lot of patients who wear hard hats or military hats. My general rule of thumb is two weeks. Now, there is really no clinical study on this. It also does depend where your transplant grafts where placed and whether the straps will be actually on the hair follicle or not. However, by two weeks you should be fine.  

yes you can easily use a sport cap like hat that is hard topped  such as a diameter adjustable baseball cap even just after operation. 

wear a hat 6 days post procedure. I recommend however for it to be a trucker snap back hat that will adjust very loosely around your head. Also, you want to make sure to not fit it so low that the top of your head rubs against the hat.Although wearing a hat is ok It is preferable to wait 10-14 days before wearing one.

Although I allow my patients to cover with a loose ball cap post procedure after 3 days. I recommend waiting 10 days before wearing a hard hat.

Generally it is best to wait a full 10 days to start wearing a hat after a hair transplant procedure if possible.

You can wear a loose hat after a couple of days post hair transplant surgery. It will not effect the results. 

I give my patients a hat in my office to wear when they leave the office to keep what they had done private.  No sweat!

It is best to wait for at least 10 days before wearing a hat of any type. But if it is necessary just be very sure that it does not rub the transplant area. Take extra caution with that are at all times and pay attention to make sure that their is no excessive rubbing.