I have two working copies of a Subversion repository, one of the trunk, and one of a branch I created.
I accidentally deleted the branch in a repository browser. How
Assuming your last revision was 108:
svn merge --revision 108:107 svn diff svn commit -m "Reverted revision 108"
You can also add your source URL to the merge:
svn merge --revision 108:107 http://svn/repo/
Elsewhere on Stack Overflow: Undoing a commit in TortoiseSVN