Let's start by saying that the idea of mothers who think it’s important to save some time for themselves is not a novel phenomenon: not so long ago several generations lived under the same roof so a newborn's arrival and the everyday tasks associated with it was not just one person’s burden. Compared to this, most mothers nowadays are alone with their children at home, while grandparents may be hundreds of miles away or could still be working.
All in all, even if only for a short time, but most moms can afford to have someone else looking out for their children, as most people have an eager relative or a trusted friend who – though probably after a bit of organizing – is willing to babysit for you every now and then. But even if you manage to make all these preparations, the question still arises: what will others say about leaving your child alone, just to go to a beauty salon / get a haircut / work out or just relax with a refreshing massage? Humiliating and judging moms became such a popular sport that in America it’s even got a name: ‘mom shaming’, however, is mostly based on other people's insecurities, so the only advice we can give you is to just ignore them as much as you can.