My app had mud fever soon after I got her it was all swollen and really hurt her. I read up on mud fever, or scratches and found out that if the leg starts to swell, you need a vet in there right away. Well I called the vet, she gave me cream to put on it and also a steriod to put into her food to help give it a jump start. It cleared up in a few days and havent come back yet. Also if you can, clean the area off with water and dry it with a towel. Also make sure she isn't in mud when she's turned out.