I had a hematoma on my knee from my very first bike crash, about 10-11 years ago. The thing was really internal, just swollen on the outside, so my pcp sent me to an ortho guy, who was talking arthroscopic surgery . I went for an MRI and lo and behold, it was a hematoma (which is what I had diagnosed myself with). Said doctor drained it, I was good as gold the next day.
I never tried to pass a water bottle to anyone ever again, as that is why I crashed. My leg hurt so badly, I was actually swimming for exercise (and I hate swimming), because I couldn't do anything weight bearing.
I still blame my son for this , as it was him, zooming down a hill on his cross bike, who saw me attempting to climb up said hill and said, "Mom, give me a drink," as he had no cages on his cx bike.