swollen finger

one of my acf's has a swollen finger ,and one side of it looks really red like blood under the skin its been like this for a while now. i thought it was because the water was dirty (55 gal missed last summers cleaning and had lots of algie and little tiny worms all through it) so i cleaned out the 55 gallon and i have them in a small critter container changing the water every couple days or so to try to get rid of the worms, and i thought that it would just get better by its self but its still the same size as it was. i dont know what else to do ? im afraid to use any medicine because theyre frogs. i dont know if it has any thing to do with the other frog but one of my other frogs is rather skinny although i make sure to feed each of them the same amount more or less hes still acting the same so i dont know if any thing is wrong please help ive had these frogs for 4 or 5 years now i dont want to lose them

ok so now the finger looks like its broken but actually has looked a lot better not being red or swollen anymore. i really just dont know what to do for it. he also has a kind of a lump on his back now about as big as a pencil eraser or so. the one that was skinny looking now looks a lot better ?? dont know why, but im glad. but ive also noticed on all three of them that on the bottom of their feet it seems like i can see their skeletons and ive looked all over but cant find out if this is some health problem or if its just normal and im just noticeing it because all of the other things wrong