"Until tomorrow" is an Instagram challenge that encourages users to post embarrassing, unflattering, or funny photos of themselves to their main account for just 24 hours.
Here's how it works:
1. Post a photo or a series of photos that fit the challenge, with the caption "until tomorrow" or the hashtag #UntilTomorrow.
2. Leave the photo up on your main account for 24 hours.
3. Take it down, but note everyone who liked the post and direct-message them with the same challenge.