If it has injured itself there is not a lot you can do, even the most enlightened vet would have trouble taking the vital signs of a snail. It is however unlikely as they have a resilient body. It is possible that it has cracked the shell somewhere but that will heal itself fairly quickly - important you are very gently if you pick it up. Make sure you supply a good calcium source, cuttlefish bone is good.
It is best if you leave it alone. It is quite possible that it is a bit taken aback with its new environment and may take a while to settle, especially if it has had a tumble.