The easy answer is to not allow the expenditure of a point of Edge on the same roll from which you got it. Doing so would be a bit time-travelly.
If one were to maintain that the glitch persists following a re-roll or extra dice then it's easy - extra hits both increase the success and lessen the glitch. For a critical glitch I think the text on p.62 implies otherwise - when using Edge to downgrade to a normal glitch* the character still fails the test. To my mind then any extra hits gained from post-roll Edge should be worthless if the critical glitch is still in effect.
* I have only now noticed that the critical glitch section and the Edge section are at odds, one saying you can downgrade to a regular glitch and the other saying you can negate it. Don't know which I prefer yet.
If one were to maintain that the glitch persists following a re-roll or extra dice then it's easy - extra hits both increase the success and lessen the glitch. For a critical glitch I think the text on p.62 implies otherwise - when using Edge to downgrade to a normal glitch* the character still fails the test. To my mind then any extra hits gained from post-roll Edge should be worthless if the critical glitch is still in effect.
* I have only now noticed that the critical glitch section and the Edge section are at odds, one saying you can downgrade to a regular glitch and the other saying you can negate it. Don't know which I prefer yet.
Isn't a usage of burning edge to negate a critical glitch?