I worked in the garden all summer and picked up what I thought were chiggers. They eventually went away, I thought. After a frost I noticed new "spots" that I thought were chiggers again, but didn't know how they had survived the cold weather. Most of the spots are on my shins and calves, with one or two found on the bridge of my nose. I began using sterile tweezers to try to remove them from my skin. Whenever I do this, I can see little red tunnels in the wound, and perfectly round holes under the blood. When I manage to pull a few out, the blood that comes is almost black. They do not itch or cause a lot of pain, except where I've uncovered a site and it's very sore. These sites do not heal. They are very deep. Any ideas?