I found a garter snake outside friday,and brought it home, [mainly because i was afraid i hurt it,i didnt see it until i stepped on it

]
But it's already eaten,and seems very playful,though i havent taken it out of its cage,in fear of it running out and the dog getting it or something
but as far as i can tell,its in good health..but ill guess ill know for sure when i take it to a vet