Hey Justin...just happen to me about 10 months ago...:(
Well...I think it may be time for a knew one??? If you have been using (and sharpening) if for twenty years...and now...lost 1/2 inch (plus will lose more in reshaping) you maybe out of the "tempered edge" zone of this gouge and its working life perhaps is at an end...
Some smiths will "reforge with the stock left...
As for trying to grind and/or cut it...and see if it will take a sharp edge again...I have used a diamond (or other type) cutoff wheel with water running on it while I cut...checking every 20 to 30 seconds to make sure there was not heat build up. I have also had susses with just "grinding" at it with a 150 mm to 200 mm grinder after placing the chisel in a freezer, and having water with ice near by to quench it...you must whatch your "colors" and make sure not to grind a new color into it. The later is much more risky!
Good Luck,
j
