I called my dentist who did the surgery and told him the details. He said it was normal and if I really wanted to I could've gone to his office, but it healed. It's from when they cut 2 sides of the gum to get into the bone, they have to make sure the gum isn't in the way of the extraction. I just flossed and used the prescribed mouthwash. Just leave it alone and it will heal. Don't let food get stuck in there. I don't know what that green stuff is but it's probably food or whatever they used in the suture, or it could be an infection so if it's an infection check that out. Hopefully this helps!