Invitations question

I think it depends on how they look. Since you DIYed them, it could be salvageable without a complete redo. Show us what they look like.

I think it would be nicer to reprint them but if money is really tight and that's not an option I think you could probably make it work in an artistic/funny way - sort of like the postponement announcements that say "oops" or "plot twist". So if you can't reprint I'd probably add in something at the top along those lines and then have the date crossed out with the new date next to or above the old one but it needs to be very clear what the new date is.