Get new blades. Carry a spare set, or at least have them in the car. You can't touch them up yourself.
Never, ever, ever let some knucklehead touch your auger. You need a light touch putting the blade to the ice, never, ever bang it down. Treat it well and you will never be sorry.
I cut with a five, carry a gaff, barb bent down, and only lip gaff. Only once in forty years a had to cut the hole bigger, and the gaff got me the 8.5 bass for a kiss and quick release.
If you respect the blade, it won't fail you. I've cut for years with the same five/six inch mora hand drill, same blades year after year and rarely if ever had a problem. Grease the blades at seasons end, carefully, grease a cloth and wrap the business end and stow them for next season.