Two days with what I think is a spider bite. I had a dark crater the size of a penny and the swelling the size of a half dollar. Made a thick paste and had it cover the crater and red area. I then used a big adhesive band aid to cover it. After four hours, I looked at it and the selling went down to a quarter. But the crater is no longer a dark color, it's white. Also, it is no longer a crater. Meaning, it filled up no longer be crater. Reapplied baking soda. Waiting to see results later.