What Causes A Sore Lump On The Outer Ankle?

A couple of weeks ago I was doing a flip off of the high bar at gymnastics and hit the outside of my left ankle of the bar in the process. It got a brush burn and a little bruised but never really swollen. A couple days later I realized that there was a bump above the medial malleolus(?) on my outer ankle and it is still there. It doesn t hurt at all when I m walking but it does hurt if I touch it a lot.