Cut inside my mouth, how to get rid of pain?

The other day I was playing with my dog. Sometimes she gets a little too crazy when we play and she scratched the inside of my mouth. She cut a vertical line from my lip to my teeth, and another cut on the outside part of my lip. The one that's been bugging me the most is on the inside. It turned white and looks like a canker sore, but I don't think it is one. It's so painful that it stings whenever I eat, and honestly for the first few hours after I wake up I cannot open my mouth at all or else it feels like I'm pulling it apart.. I looked up ways for it to heal faster but just the idea of using lemon water or salt water sounds so bad. I'm not even exaggerating, I have a VERY high pain tolerance. I ran for 5 weeks straights on two broken bones, and this cut in my mouth STINGS! Also, what's a way to make it just not sting as much? I took some motrin and it did absolutely nothing.