For some time you have the option on WhatsApp to delete the messages you sent. But the next step would be for the message to disappear by itself for a while, so you don't have to worry. And, well, the information so far shows that this scenario will become a reality.
Messages that "self destruct" sound like something you would like on WhatsApp. Or in any chat application and possibly even mail. Telegram, for example, has already offered something like this. And Facebook has experimented with the option in Messenger, in secret conversations.
What could get WhatsApp from Messenger
Although the secret chat option in Messenger is less popular, it has been around for some time. Thus, when you initiate a secret chat, the messages are encrypted and you can set a time after which the message disappears. You have from five seconds to a day with various intervals between the two. The message remains in the chat until the other person reads it.
The WhatsApp option was discovered in a beta version of the app, for Android. It will definitely be available for iOS when it is released.
For now, it's in a rudimentary form. You have either five seconds or an hour after the message disappears. However, the easiest way would be to take the features from Messenger.
Until this feature is available, it is good to know that WhatsApp also allows you to delete messages. As long as you don't forget, it can be a solution. You have about an hour available if you want to withdraw what you said or if you sent pictures that you would not like to see the other person.
With self-destructing messages, but also with the ones you can delete, a golden rule remains active: if something is too sensitive to write in chat, you better not write it.