Saw the GP today about the suspected stitch. It turns out that it is a stitch, and he thinks it is probably attached to more beneath the skin.
He went out of the room and came back with 2 pairs of scissors and a bunch of gauze (the stitch is well covered by skin and he was going to pry it out). He casually said, "it will probably come out on its own if you leave it". So I must admit I chickened out, and told him I'd rather wait for them to come out by themselves. I thought I'd had enough pain in that area without somebody poking around with more metal implements..
Here's hoping they come out soon!