Eyelashes are hairs, so they fall out naturally from time to time. Like the hair on your head, they also grow back on their own. When an eyelash falls out, that. When an eyelash falls out, it can take anywhere from a month to six weeks to grow back.
There are a lot of reasons why some people don't have eyelashes. Some people are born without the ability to grow their eyelashes. Others undergo cancer treatments that cause their eyelashes to fall out temporarily. However, other people suffer from diseases that cause them to lose their eyelashes.