I Have A Spot On My Upper Leg That Itches

I have a spot on my upper leg that itches for weeks at a time. It will clear up to barely there with no itching. Then it appears again. It feels like there's something inside wiggling. Now I have a hematoma around it that is approximately 3-4 inches in diameter. Also now there are large hematomas all over that leg...top to bottom. Doctor said he thinks the "bruising" may be a burst Baker's cyst. Could the original small spot be a recurring infection from an insect bite, that is further infecting me? The doctor ordered blood work but I don't why.