How Can A Painful Lump At The Injury Site Be Treated?

Hi, I whacked the ball of my foot on a curb last year. Was VERY sore for about 3 months. I assumed it was just like a stone bruise but even after the intensity subsided it is still hanging on which makes it impossible for me to run/tennis. I thought possibly I had torn one of the ligaments/tendons that spread from the ball of foot to the toes (and might be the case) but then I spoke to someone who had a similar injury and he said something about a scenario where an air bubble/blister can occur under the skin and mine might be pinched against a nerve. Can t remember what he called it but anyway looking for answers/solutions. - Thanks, Grant Garland