I hate to break it to ya, but grill starters are piezoelectric. Once they're broken, they're broken. You'll have to get a new one. But first, check to see if/it's/because/it's/out/of/battery.
Find your grill makers website/telephone number and order a automatic ignition, all directions will come with the part and the starter will work like new again.
Figure out the name of the company thats makes the grill. You can go online and get their number. When you call them let them know you need a new starter and you can buy one. I would recommend getting a pro to put it in but the company may be able to help with that too.