Could be a few things.. anything from simple insect bite to inflamation from broken bone or abcess. One of those toes looks concerning.. not sure if it's a shed or actual to damage. Try to see how well the hand and toes work.
And you should ditch that coconut fiber. It has sharp rigid edges that will cling to and rip up intestinal wall when injested. Can lead to a blockage which is easily fatal in reptiles.