I use beer smith and brewed a dark belgian, beer smith tells me to use however many oz of priming sugar for correct carbonation for the style. I do so, bottle and when I have 10+ extra bottles left I realize that I lost about a gallon during a fermentation accident. So should I be afraid of exploding bottles since I used sugar for a 5gal batch on a 4gal batch? What can I do to fix it if so?
Don't worry. At worst, it'll just be slightly over carbed. You'd have to do something like put a 5gal dose of priming sugar in 1 gal of beer to begin worrying about bottle bombs. From what I understand, most bottle bombs come from bottling too early.