I had mine out under GA during my teens as well. Mine where under my gum so an incision was made in both cheeks and they tunnelled down to where the teeth were and pulled them out through the inside of my cheeks.

I wasn't in pain after wards, it just felt like my mouth was filled with cotton wool but really there was nothing in there and just very swollen. From about lunch time the same day to 9pm I slept only waking up to spit out some pooling blood from time to time. The pain really didn't set in until the following morning and I felt pretty sick but was manageable.

I had dissolving stitches and the knots fell off after a while, the biggest pain was having a mouth full of food then realising I'm chewing on a knot and having to fish it out of my mouth.

It wasn't a pleasant experience but it certainly wasn't the worst thing I've ever been through.

Hope it goes well and you get in soon!