What is the area I circled in the photo

Hairs grew in the area I circle before and now there are no hairs there. Does that mean that no hair will grow there again?

Although the area where I placed the arrow previously had hair growing out of it, maybe it was a one hair follicular unit and the hair went into the Catagen phase of the hair cycle and disappeared.  If that were the case, it would come back within a month or two.