Caring for an Injured Grasshopper?

I found a grasshopper in the middle of the path. I discovered it was a bit black and burnt underneath and looks a bit swollen. I've put it in a net butterfly house. It's not really hopping and is a bit wobbly, but is wandering around.

Is there anything else I can do to help the poor fella, or would it be really suffering and be kinder to euthanize?

By Jess