Its might be corrupted, if you need to back up the data connect it to other sources like PC and retrieve it. If its says corrupted on PC then you only choice is to forget about the data and try formate it. Also it maybe permanently corrupted or have issues with file system. There is Storage softwares for pc that can help you remake it. Most common issues is when you set your SD to be part of the phone storage or to be encrypted in this case after you reset it like putting it in the new phone which is not encrypted to be used with it anymore. Overall, most likely your card is done for. But won't hurt to those options. Also try to clean the connections on the card with Medical Alcohol.