If skin is cut, you can move frog to a hospital like enclosure with damp unprinted paper towels as substrate to prevent it from getting infected. A daily application of an antibiotic (either plain silver gel or plain Neosporin with no pain reducers) should help too.

While in there, need to investigate what could have injured frog and if found, remove cause from it's enclosure (i.e. sharp plastic plant or decor). Once frog has healed, can move back into it's regular enclosure. Good luck !