Hi Doc! 55 yo woman here. I have what appears to be a large bruise on my right knee. It appeared from nowhere and has remained bluish purple for 2 weeks. It s painless and the discoloration disappears when I take a hot bath but the color returns to bluish after about 15 minutes. I had no injury but I did wake up a few weeks (before the discoloration) ago feeling like I was bitten by maybe a spider and did have a small bite that was very itchy. I have no other symptoms and don t feel unwell in any way. Should I have the knee looked at? Thanks for your advice Karen