Pain in my gums, what should I do?

4 days ago I felt a piece of food in the back of one of my back teeth. I was an idiot and tried to pry it out with my fingernail and I accidentally scratched the back of my gum along the inside of my cheek. It was a very tiny scratch and barely any blood. I rinsed with warm water and left it alone. It is now four days later and it hurts a little more and the cut feels like it's more open. There is no sign of blood and it doesn't have any colors or infections around it. It just feels like a little crater. 3 years ago I got my wisdom tooth removed from that spot, I'm wondering if I accidentally reopened a stiching. Or is it just a wound trying to heal itself? It's not painful, just annoying. It was at it's worst 2 days ago and is slowly feeling better. Should I let it be or do something drastic.