Someone else I know had surgery not too long ago, and she was also afraid. The docter prescribed her a medicine that makes you relax a lot (you will nearly fall asleep), after she took it, she was so sleepy that they just used some gas and she can't even remember it. So if you can get some of that medicine, maybe it can help you relax a bit before surgery, so you don't have to be scared for the gasmask.
That "medicine" was probably valium.....
That's what they gave me + IV, when
I had all four of my wisdom teeth taken out in one shot(about 8yrs ago), afterwards you couldnt even tell I had anything done, no swelling, bruising or pain at all. Although the pain may have been taken care of by the T3s.
It did bleed a bit though had to keep a bunch of gause in my mouth for few days and I couldnt participate in PE class for a couple of days. Eating was also abit difficult but not for long.
One of my brothers also had his wisdom teeth taken out, he was pretty swelled and bruised, lasted about a week.
From what iv seen everyone has different effects after having their wisdom teeth pulled out, so it could go either way but Im sure it wont trouble you too much.
Dont worry about, consider what would happen if you didnt go through with it.