Mud in a wound

My MC has had to make a run for it without taking time to put on her shoes. She now has a couple of good gashes on her feet from sharp rocks. Since it was raining, her feet are caked in mud and the cuts are inflammed. They don't have a way to wash, so they've wrapped her feet in cloth, but it will be a couple days before they can properly care for them. I'm not looking for anything gangrenous to happen, but exactly how bad would her feet be by the time they could get her off them and properly try to heal them?

In the thread here:

http://nanowrimo.org/en/forums/reference-desk/threads/49888

someone mentions "cavers' tattoos", which are apparently the dark patches of skin you get from wounds healing up over mud. If you want inflammation and infection, however, you could be looking at wound fever and yes, gangrene.

Depending on where the mud is located, there could be some nice little parasites, little wormy things to work their way into the wounds.

Thanks, I'd already thought of the natural tattoos thing, will have to spend more time reading up about infection...

And the worms are a good idea, hadn't thought of that. They're in Wales, so maybe there's something there...