<s>[INST] I slipped and fell at a store about a month ago and smashed my shin against my shopping cart.  It immediately made this like blood blister on the shin, swelled a little.  A month later I have this noticeably hard but tender lump on my shin that seems a little swollen.  Could this be a blood clot? [/INST] Hello! Thank you for the query. Yes, this might be a blood clot. Especially if you have any varicose veins in this area. Injury is a very common factor of veins thrombosis. If you do smoke or take some hormonal pills (like contraceptives), the risk of thrombosis is higher. Such lump can be also caused by blood accumulation under the skin (in soft tissues). This is not related to the veins' thrombosis. I suggest you to consult a surgeon with this issue. In case of doubts, ultrasound should be done. Hope this will help. Regards. </s>