Hi Doctor. I was out with friends 2 nights ago and felt what seemed to be a bug bite on my neck. I flicked it away as soon as I felt it, unfortuntely I didn't get to see what type of bug it was. It swelled up a little bit just around the area right after, like a big mosquito bite and it didn't concern me much. Then I woke up the next morning with the area now a 1/2 inch dark brown patch on my neck that looks like a birthmark. Its been 2 days since the bite & it still hasn't gone away, and it feels a little tender, but no redness or swelling. Will the dark patch ever go away?