Thanks (to both of you) for the insight/advice, I'm still trying to get by buddy over here with his camera!

It had not moved in 3-4 days, it was just hiding out under a rock. I took him out just now and it looks a lot better! I can still see a small indent on its leg but it does not look raw anymore and there is no fluid.

So hopefully whatever it was is gone, but we shall see. I will update with better pics hopefully tonight.