Horse's hind leg is extremley swollen

Friday morning me and my sister went out to the farm to feed our horse when we noticed her standing funny. When we called her she didn't come to the gate which isn't normal so we went in put a rope on her and tried getting her to walk when we noticed her left hind leg was severley swollen. It isn't her ankle its right above her ankle and up. We tried getting her to move but she wouldn't she won't put any weight on that leg she holds it up or rests it on her toe. We called the vet and the vet couldn't feel if something was torn or broken because her leg was super swollen. He tried to get her out of the small pasture she is in and into shelter near electricity to give her xrays but he could not get her to move she will only hop around on her own will. She does hop around to get food and water because when we go to check on her she is always in a different place. The vet wrapped her leg and gave us bute to try and stop the swelling and ease the pain and said he is coming back tomorrow (monday) to see if she has improved and then try and get x rays. However she has not improved at all she still wont put any pressure on that leg and it is starting to really worry us. We're afraid she will damage her right hind leg from putting all her weight on it. She eats fine but just looks depressed. She does not have a temperature. Has anyone else gone through something like this with there horse? Anyone know what it might be or what we should do. Thanks