Tie a sweatshirt around your pants so it will be less noticeable, if that doesn’t work, just try to get through the day the best you can without being noticed.
Just get a new email if you truly cannot remember. If you have notifications for that email, just sign up for some website and it should send it to you.
If there was some kind of extenuating circumstance, it may be reasonable to ask for an extension. If you just totally blew it off though, it's not going to be...