How do I know if I combusted?

Some of the avb had a little black in it. Not all of it did though. Most was dark brown. How am I supposed to tell. I did a little after the first click like maybe 4 seconds. There was more smoke then I have ever had with it. The highs also don't usually hit as hard as it did with it this time. Or am I just heating it up correctly for the first time. I don't have pictures sorry. I am using the m7 btw.