How many days does it takes to hide Hair Transplant signs?

You can hide hair transplant surgery signs by wearing your hair long or wearing a hat.  It all depends on how you do it, but the redness and scabs will be there for a few days. It all depend on how you wash your hair and how well you follow the post-op instructions.

Everyone heals differently and some patients
take a little longer to heal.  You should
ask your doctors what his normal healing times are.  Good luck.

It can take 2-10 days depending on your healing and how big the case is.  Also, it depends on FUT vs FUE and Neograft vs ARTAS. So every variable needs to be considered. 

The answer depends on how much "existing" hair a patient has. If a patient has a lot of existing hair, and the temples or recipient areas is being thickened up- many patients can go back to work in 2-3 days without anyone knowingIf a patient is quite bald, the grafts & crusting are visible for 2-3 weeks. Swelling (if it occurs) goes away by day 4-6. A small number of grafts might still be seem by day 21 but not in all patients. Patients with darker colored skin can often more easily camouflage the changes than patients eith lighter colored hair. 

IF the doctor does follicular unit grafting and washes it vigorously according to a routine that is well established, I have had patients routinely undetectable within 4 days when the frontal hairline is done or even within a day if combing allows a cover-up. Notice the man in the web reference combs his hair forward to cover the transplants. 

It is usually common to have the scabs visible for about ten days post op.  After two weeks you should be able to return to your airmail routine and the scabs should have fallen off.