I'm guessing it's an aquatic African Clawed Frog; right? Appears foot got caught in something or maybe the water heater burned it? Get to pet shop and buy a bottle ea. of Melafix and Pimafix or local alternatives. Treat with both daily following bottle label directions for actual water volume for 7 days and let us know how it goes.

You can also consult a local herp veterinary if available, for stronger medications. The wound should heal; the meds I listed are to prevent any bacterial or fungal infections from setting in. Good luck !