If the memory card can't be detected, it's impossible to recover the data in it. Don't know if you have tried your memory card in other devices such as digital camera or PC. Just plug your memory card in those listed devices, see if it can be detected. If yes, as to the lost photo data, I think you can rely on this picture recovery too called Wondershare Photo Recovery to recover photos
lost. Or refer this article talking about 3 ways to recover deleted pictures from memory card
for more info. If all in all the memory card is unable to be recognized, Your memory card may be corrupted, the only way to recover your picture data is to send it to a computer shop or for data recovery services.