Even after 44 days of hair transplant surgery, my scalp feels numb. When will it regain sensation?

It may take weeks to months before the numbness goes away.  Everyone is different.  If you are concerned it is best to contact your doctor.

you didn't mention which part of the scalp(donor v recipient) or which method(FUE v strip). Either way it is not uncommon to have a numb feeling for several months due to temporary nerve injury.

Numbness in the recipient area following a hair transplant is normal.  Superficial nerves branches that innervate the skin can be injured during the recipient site making process.  However, this injury is usually not permanent and those nerve endings will recover and once again provide sensation to the scalp.  Recovery time is different for every person and can take 6 months to even a year for full sensation to return. Be patient!  As always, if you have further concerns please contact your surgeon to discuss.
Best regards,
Dr. Phipps

This is not unusual- it can take several months for scalp sensation to return to normal after a transplant procedure. 

It is quite common to have numbness in the scalp after a hair transplant surgery. For the first little bit you may even experience occasional sharp pain in the donor area. This is to be expected as the nerves that were damaged in the procedure are healing. Just be sure to let your doctor know so that they can do a proper assessment and make sure that everything is healing properly. 

Persistent numbness does happen. You must realize that small nerves have been damaged that are recovering and the numbness will eventually go away, just be patient