Just in case any tanks here didn't know, you can rightclick on a buff to cancel it. I cancel Regen anytime I see it when I'm not in a fight. If the healer used medica2, that's another story, as I can't click off the HoTs on the DPS or the healer herself =\ But as someone new to healing dungeons, it's easy when underexperienced to use regen at the end of a fight not realizing it's the end of the fight. Often, I'm watching the party menu far more than the monsters' health bars.