She acts completely normal, she is actually very lively! The injury was noticed about 2 days after she was born so about 2 weeks. My guess is she got bitten by some sort of bug. I have just began treatment since it gets larger. She only stays with her mommy silkie and her 9 siblings.
I would think after 2 weeks it would be getting noticeably better. My two best guesses would be an insect bite like you think, if so you should be seeing much improvement over the coming week. My second guess would be some sort of CA (cancer).