# Run this command:
git reflog

# Scan the first few entries, and find the commit that was lost.
# Keep track of the identifier to that commit (you can use either the 1st or 2nd columns).
# Let's call the identifier "ID".
# If you have not made any extra work since you did the reset --hard you can do:
git reset --hard ID
git push -f origin master

# If you have made other work since the reset,
# you could cherry-pick if back onto your branch like this:
git cherry-pick ID
git push origin master