As the growing period of hair in these locations is about six months before it goes into the resting phase and falls out, the hair is much shorter than on the scalp. For this reason, it is common for disorders of hairs here to become cured spontaneously. The hairs simply drop out, the disorder disappears, and new hairs grow automatically in due course.
Hair in this region grows at about half eyelashes and eyebrows have a primary protective function, as well as enhancing the facial features the rate of scalp hair. Therefore, plucked eyebrows will grow back to normal in about one month.
There is no way of increasing the rate at which these hairs will grow. Despite efforts to enhance their speed, or to make eyelashes grow longer, there is no know: method, nor is any likely to come in the foreseeable future!
Young women often develop a fixation about their eyelashes and eyebrows, but nothing can be done to improve nature. Keeping these areas clean at all times is the best advice that can be offered.