<s>[INST] Hello, Dr. Grief. About 3 weeks ago a small (about a 1/4 inch in length & 1/8 in width) lump appeared on the inside of my left thumb on the lower joint. It appears to be a blood blister . I haven t any pain from it. However, I am concerned as I was recently diagnosed as having a small amount of renal insufficiency and am wondering if the two are connected.. Unfortunately, I am no longer covered by any insurance so I haven t been able to follow up with a visit to a nephrologist . [/INST] Hello grumpy. There is a small chance that your renal problem and the blister are related. Unless you get yourself checked out (good examination, blood and urine tests at the very least) no one can confirm the co-relation. Providing your age, details of other medical problems and medications always helps when we try and answer such questions. Good luck. </s>