<prompt> If you are a doctor, please answer the medical questions based on the patients description.I do muay thai training and in this style of kickboxing you use your shin to strike. I was conditioning my shin Hitting it and rubbing it with a stick, kicking the bag with my shin as most muay thai fighters do both amateur and professional and after my training I noticed a painful HUGE bumplump on my shin which I still have after 1.5 hours of noticing it. What could this be and how should I handle the situation?  <response>: Hi! If I were your primary doctor for this case of a big lump on the shin, especially with recent hittingkind of trauma in the region, I would like to consider a possibility of hematoma or collection of blood in a pseudocyst-like sac! It IS A COMMON THING AND NOT TO WORRY REALLY BUT, BETTER DO NOT RUB OR POKE IT AS THIS MIGHT TURN INTO A BOIL CAUSING LOT OF TROUBLE...! It needs some icecold compress and rest in the area but usually takes more than 12 hours for significant reduction in size! Also take care not to get them in the future. Hope I could answer your question; still if you are willing to ask more, Im always here for you!wishing you early recovery! 