How Can Swelling In The Knee Be Treated?

Hi there, About three ago (sunday), my left knee substained a hyperextension injury on a fall while I was snowboarding. My knee was swollen and and smallest movement hurted me alot. I went to the emergency room in hospital, where I stayed about a day and half. They did a Xray that revealed no bone breakage and a ultrasound scan which the results were not disclosed to me. I’m attending an MRI soon. I was handed a brace and a pair of crutches. They send back home on Monday evening. Since today, Wednesday, I saw bruises about four to six inches long in a form of strips on the back of my left knee that that were not there since the incident happened and I wanted to know if it’s normal or if it’s require a medical attention. Many thanks!