I forgot to mention another way to liven up a lethargic frog is to give it a bath with water and a little unflavored Pedialyte to restore its electrolites. Or if you just want to energize the frog enough that it might try to eat, a bath with a drop of honey might do it. The honey thing is also used in frogs who have impactions/constipation.

Vitamins can help prevent eye problems but that kind of looks like an injury to me. I don't know though.