Not bad. I think I was clenching my jaw, because I had a headache when I woke up. It’s gone, now.
I’m glad your headache was fleeting. I also hope it stays away for the entire day!
At one point I got a tooth guard from the dentist because they thought my nightly jaw-clenching was breaking my crowns. Recently I decided its fit was so bad it was messing with the spacing between teeth so I stopped using that custom made job and started using an off-the-shelf brand from Rite-Aid.
I don’t know if it would help with headaches, but my crowns are lasting longer.