Is it just me or does that large blister look like it's deflating a bit and starting to crinkle up near the front? It's good that he's still actively seeking out water at any rate.
It does look like it from the picture. But really, the fluid doesn't fill the whole blister. So when he's at an angle, it all sinks to one end and the other looks empty. :/ I thought the same thing when I walked in and saw that.