Is eyebrow threading permissible if it's done for oneself, and not to show off?

Nowadays, women and girls have shape their eyebrows, such as through eyebrow threading (which may extend to the full face). My opinion is that most of them do it just to show off. However, if this activity is just for oneself, and not for showing off, such as inside the house and while observing hijab, is it allowed in Islam?