Does anyone know what this is?

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Sorry it looks kinda gross. I woke up this morning and my knee is very hot to the touch, and it burns/itches and is swollen.

Update: I’ve been sitting down to see if that helps the swelling and this is how it looks now