QUES: You will only be able to use it during a limited time

correct the punctuation.

CORRECTED: -You will only be able to use it during a limited time.

QUES: The type of incision that is normally used for forehead lifts should rather not be used on men since they expose more and more scalp for hormonal reasons in the course of their lives Here we usually reduce the forehead skin directly above the eyebrows along a small wrinkle

correct the punctuation.

CORRECTED: The type of incision that is normally used for forehead lifts should rather not be used on men, since they expose more and more scalp for hormonal reasons in the course of their lives. Here, we usually reduce the forehead skin directly above the eyebrows along a small wrinkle.

QUES: How can I know whether I eat an authentic and not a fake food

correct the punctuation.

CORRECTED:
How can I know whether I eat an "authentic" and not a "fake" food?