Dave's ESL Cafe's Student Discussion Forums

[sejpdw]

You accidentally ran a document that your boss wanted to be photocopied through the paper shredder. Or you forgot all about an important appointment you had with a client. Oops! But the mistake has already been made. And before you bury your head in a sack and wave a despondent goodbye to your career, remember this- what you do in the immediate aftermath of an error may well determine just how big the issue burns. No mistake is as bad as your indifference to it. There is no use greeting stressed about an act that has already been committed, but if you can prepare an action plan for recovering form the situation, you will find that there is a lot that you can do to repair the damage caused.

What's the meaning of "how big the issuse burns" and what's the part of speech of "big" in the sentence?

[pugachevV]

Just how big it burns is colloquial and ungrammatical English.
Translated, it means: What you do immediately after you have made an error may determine how much trouble you get into.