Could my husband have a bloodclot in his leg? my husband is 40 and overweight with a history of knee and back troubles. his knee recently swelled and became painful with no obvious cause. he has been doing yardwork instead of resting and now his lower leg

Well, : Well, lots of factors going on here. Given his history of knee issues, a day spent doing yard work certainly would aggravate this, and even cause swelling... In the knee, but not the lower leg and ankle. And the mottling you see is probably not from a close exposure to a heat source. When i barbecue, i usually end up burning the hairs on my arm long before I do anything to my skin. And the skin's response to heat is to turn red at first (before it blisters), so i don't think the mottling is from the fire. So my short answer to your question is yes, take him to the doctor and get him checked out. It may or may not be a clot, and it may or may not be dangerous, but why take chances? If it is a clot, it can be a serious problem that needs immediate attention. Better safe than sorry. Good luck!