I'm 19, athlete. had wisdom teeth removed a few days ago and as they were waking me up from the iv sedation, hr was high- about 115-120. why is that?

Elevated HR: Unlikely that this is any cause for concern. When waking up from any anesthesia/conscious sedation there is some “adrenaline” release increasing HR. Local numbing medication used by dentists usually contains epinephrine which is a stimulant that is absorbed and leads to elevated heart rates. A heart rate of 115-120 is likely just a fast normal heart rhythm or what is called sinus tachycardia.