Lamb milk is fine, but you need to add some vegetable oil, as pig's milk has a higher oil content. Any veg oil will be fine, and just add a little to the mix- say teaspoon to 1/4 cup milk - don't worry about exact amounts -you are just trying to keep it alive, not grow champoinship stock!
They feed very 1/2 hour or so, and their tummys hold very little, so it is a challenge to keep them going at that age.
If you have a creep area, I would rig a lamp up and put it in there, that way it'll keep the herd smell, and re-integrate quicker as it mends. You can then still feed it there. If you don't have a creep area, suggest you try and improvise one.
They mend pretty quick sometimes - crawling at deaths door in the evening, running round in the morning - depends on what damage she has done, but may well just be a bruise.
But a Lillian says some you win...