If you have used the 'Delete' button as opposed to the 'Delete Forever' button, then you can restore the contact. Go to the Customers tab > Contacts > click on the hamburger menu on the top left on this page and click on 'Deleted contacts'.
This page will list all the contacts that have been soft deleted (using the 'Delete' key). You can click on the contact and use the 'Restore' button to restore the contact. The contact will be restored to just the way it was earlier.