hello i have gone through your query. the thing you are having is an hematoma- a blood collection between the tissues under the skin. it happened because of straining, the artery which was cannulated had a small leak when you strained. you must watch out for increase in sizeof the swelling. please contact your doctor. allow rest to the limb affected including weight bearing. also if possible keep a cold compress. it may be red now. and the color may vary from red to blue to green to yellow before disspaearing. it will take around 15-20 days to dissapear. however increase in the swelling should be check for. you may also be adviced to undergo a sonography of local area to see the extent of the hematoma if its quite large or your doctor thinks so. thank you.