This is good advice. I had an implant post hole screwed into my jaw a few months ago. During the initial consultation I honestly explained I get anxious and asked about what kind of drugs I could get. The dentist was literally like "oh we usually prescribe what I like to call 'happy pills'" which turned out to be some kind of benzos. I also asked for nitrous. It was a total non-event, I don't remember it at all, and experienced no pain (that I can remember). Also the initial local anesthetic shot you get in the gums is about 50x worse mentally than physically. It hurts way less than when e.g., you bite down hard on a sideways tortilla chip fragment and it gets jammed up into your gums.

So just be honest, ask for meds, and be proud that you're taking care of your health and your anxiety.