Rollback ports to before mate update

Mate was updated to 1.26 and it blew up on me. I have no usable desktop and
want to rollback my git clone of ports to its state yesterday. I have the
commit hash fron yesterday morning, but I'm not sure how to get there. I
really hate to completely blow my ports tree.

I'm guessing "git reset" might be what I'm looking for, but I'm far from
sure. Help!