How to save pics or recover if have to format so card on Nixon l830
Formatting will always make it worse, so don't do that.
There's really nothing you can do that won't risk further data corruption, so you need to send it to a data recovery lab that can recover from monolithic flash devices like SD cards and hope that it doesn't require a rebuild.
Stop using the SD (or CF) card. Remove the card from the camera and insert it into a card reader connected to a computer. Use a good data recovery program from one of those listed below. Start with RECUVA.